Honestly, I have never seen equation systems solved in this way. At my school we always isolate the first variable, so it can be but into the next equation, to solve the next variable so it can be put into the last: so you'll end up with an equation with only 1 variable. Therefore this is mindblowing to me. Thank you!
Recently went back to university for a new degree. First time I've been in classes in about ten years. Algebra and trig are absolutely killing me as I'm realising how utterly weak my foundations are in most maths at the moment. Your channel has been amazing to help me relearn and catch up on things. I'm still far behind, but you definitely help relax some of that stress. I will always smash that like button.
I was in the same boat. 12 years since I had taken a math class and jumped into pre calculus algebra. Just keep trying and don't give up. If you fail a class take it again and consider it a learning experience. In a year you will be amazed how much you have learned and what you can do.
You are the best teacher I've ever seen even my lectures don't explain like you..... we appreciate your assistance, may God bless you with more wisdom and knowledge.......❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤
I was watching a video, made by my school, which explained this topic... it was not helpful. After a bit of searching, I found this video and now I understand how to solve a system of equations with 3 variables in it. Thank you.
Thanks for the videos , pre calc is kicking my butt right now but I’ve been pulling through with these videos and they are way easier to understand than my math teacher. Keep it up. 👍😊
1 - Spend one second looking at the exercise. 2 - write it wrong. 3 - spent houres trying different increasingly complex methods to solve an impossible equation.
You have to get rid of one variable, in this case Y was just easier And he multiplied following equations by -1 so they could subtract eachother rather than just add Hope this helped
Like if u did this (4x+3z=13)-2 (5x+3z=14) It would come out like this -8x-6z=-26 + 5x +3z=14 -------- -3x-6z=-12 And so it would not have been able to subtract anything or delete any variable@footballomega
“A, B, and C have 2150 yen collectively. A has 120 yen more than B does. After C gives B 2/5ths of his money, B now has 220 yen more than A. How much money did A originally have?” They say it's a problem that even middle schoolers can solve, but wow. Maybe I'm just dumb. I can't figure anything out. (B+120) + B + C = 2150 An + (B+2/5C) + 3/5C = 2150 ?
A = 710 B = 590 C = 850 A originally had 710 yen. The A, B, and C values are all BEFORE they gave money to each other. I was able to gather the following equations from this problem. A + B + C = 2150 A = B + 120 (2/5) C + B = A + 220 Now I will replace "A" with "B + 120". (B + 120) + B + C = 2150 (2/5)C + B = B + 120 + 220 In the second equation, it looks like I can solve C since the B's cancel each other out. (2/5)C + B = B + 120 + 220 (2/5)C = 340 C = 850 Using C, I can solve for B in the first equation. (B + 120) + B + 850 = 2150 2B = 1180 B = 590 Now, I can use the very first equation I wrote and solve for A. A + 850 + 590 = 2150 A = 710 I can now use the three original equations and check my work. 710 + 590 + 850 = 2150 710 = 590 + 120 (2/5)850 + 590 = 710 + 220 The above statements are true. Unless you find that my original equations are incorrect, this is one way to solve.
The reason you have to multiply the first equation by 2 is so the Y’s cancel out. At first you’ll see that the first equation has y and the 3rd has -2y. Since we’re trying to cancel them out they have to have the same value with opposite signs, which would be 2y and -2y. After you multiply the 1st equation by two now the 1st equation has 2y, the 2nd equation still has -2y so they cancel out when you add. You would pretty much follow the same logic for the one that gets multiplied by -1, it’s to make it so one of the variables gets canceled out. Also, incase you were confused on this multiplying the whole thing doesn’t matter because it can still be divided by that same value to get the original equation. I hope this helped! :)
So he multiplied by -1 because he want to do it more simpler so he can do it and also because subtracting is kind of confusing when you have a negative stacked on top of each other you can accidentally miss the sign and that will ruin the whole thing. Example: 2x+y=7 11x+2y=20 ------ 2x+y=7(2) 11x+2y=20 - ------ 4x+2y=14 11x+2y=20 - -------- 7x=7 x=1 ( I know this is wrong because the x is supposed to be negative because 4-11=-7) So we sub the x=1 into prob 1 2+y=7 ---- y=7-2 ---- y=5 BUT if we do it the right way where x is equal to -1 2x+y=7 ---- -2+y=7 ---- y=7+2 ---- Y=9 As you can see if we get the signs wrong on the first one that you solve it will become wrong for the entire thing
My ONLY problem with this video is how he solved the first equation. I have on my paper a problem that can’t be solved with that second equation multiplication, so I need to have a different set of steps to complete it. This video only does something you can do in a specific group of situations, and doesn’t help when the 3 variable system of equations isn’t able to do that last elimination that you did. It would help many people to see how else you can solve a system without that last shortcut.
Actually solutions can be presented as { (1,2,3) }, representing the "set" of all possible solutions to the system. Since each equation represents a "plain ', three plains have only one point in common.
But what can you do if the factors of the variables aren't constants so you can't cancel. For example: x*sin a + y *sin b + z*sin c = 0 x*cos a + y*cos b + z*cos c =0 x*sin a * 2l + y*cos b * 3l + z* sin c * 4l = 0
I got it ! He multiplied the first equation by 2 so that the 2y in equation 3 could be cancelled out. Same applies to the 4th equation that was multiplied by -1
My problem is I don’t understand how your getting negative numbers to divide the equations by (5A+8b=6.55)(-7) 9a+7b=9.20 where does the -7 come from does it come from reversing the 7b?
Pretty sure im a bit late, but it is because you would need to have two equations with only two variables to make this work, and he had chosen Y to be taken out, and the top equations Y was 1/2 of the third equations Y so to make them the same value so they cancel out, you have to multiply the whole top equation by 2 so when you add the first and third equations, the Y cancels out
you multiply one equation by a certain number to make a specific variable cancel out, like if one equation was : 2x+3y+2z = 25 : and the second equation was : 5x+7y-z = 25 : and you wanted z to cancel out, you multiply the entire second equation by 2 so -z could turn into -2z which cancels out the first equation's z which is positive 2z
1 was your x variable which he got in the first equation, in order to find z, he had to plug the x variable to the 5x. which makes it 5(1) aka 5 times 1, which really is just 5, but you still need to include that variable even if it’s just a 1.
Matrices - Free Formula Sheet: bit.ly/3UE9Cmk
System of Equations: www.video-tutor.net/systems-of-equations.html
Honestly, I have never seen equation systems solved in this way. At my school we always isolate the first variable, so it can be but into the next equation, to solve the next variable so it can be put into the last: so you'll end up with an equation with only 1 variable. Therefore this is mindblowing to me. Thank you!
this ia elimination method suitable for some equations...
Recently went back to university for a new degree. First time I've been in classes in about ten years. Algebra and trig are absolutely killing me as I'm realising how utterly weak my foundations are in most maths at the moment. Your channel has been amazing to help me relearn and catch up on things. I'm still far behind, but you definitely help relax some of that stress. I will always smash that like button.
Hope you’re doing well because I’m taking AP Calculus BC. Ext year as a sophomore
I was in the same boat. 12 years since I had taken a math class and jumped into pre calculus algebra. Just keep trying and don't give up. If you fail a class take it again and consider it a learning experience. In a year you will be amazed how much you have learned and what you can do.
I am in the same boat lol, these videos are bangers.
damn i’m in 11th grade and this is the standard class for this grade
Online class? ❌ TH-cam class ✔️
hell yeah
@@fabianousim6716 yeah bro this dude is insane
exactly👍
@@afifmasian7685 sometimes we need a best tcer to teach maths
Factual
I learned this originally for Algebra 2 but now 4 years later I need it for linear algebra. Thanks for the video!
Thank you so much. I've been struggling for 5 days LITERALLY. your video made me a pro with this ☺️
this guy does a better explanation than my uni lin alg textbook ever did
Wish me luck for my final exam❤
Good luck man. Wish me luck on my midterms
MR. Organic Chemistry Tutor, thank you for another great video/lecture on Solving Systems of Equations.
my math teacher doesnt teach us and this helped me tremendously on a quiz that we had. Amazing!!!!!!!!!!!!!
Thanks! This video really helped me with a question on my math final!
same
Thanks ❤❤
You are the best teacher I've ever seen even my lectures don't explain like you..... we appreciate your assistance, may God bless you with more wisdom and knowledge.......❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤
Honestly, you've helped me a lot, thank you tutor
I love this guy, always helps
Do some word problems using 3 variables...
I guess I am kind of off topic but does anybody know of a good site to watch new movies online ?
@@andreclay9324 myflixer
@@andreclay9324 very off topic
@@andreclay9324 lol what
@@andreclay9324 egybest
This video just saved my hope for better grades. Keep it up
I was watching a video, made by my school, which explained this topic... it was not helpful. After a bit of searching, I found this video and now I understand how to solve a system of equations with 3 variables in it. Thank you.
Always really helpful when I forgot or when I just learned a formula, thank you kind sir
2am and i have exam at 12 pm, was only stuck on this one. thank you for hammering it into my head.
not gonna top but not gonna fail either
I'm in 3rd and going to kumon and I LOVE your videos, you helped me with level G.
you’re literally the best
Thank you for this! My teacher speaks and works really fast and it’s hard to catch it all, so I really needed this :)
Super simple, easy to understand
You single-handedly saved my grades
Thanks for the videos , pre calc is kicking my butt right now but I’ve been pulling through with these videos and they are way easier to understand than my math teacher. Keep it up. 👍😊
Hopefully this video can help me with algebra 2 this year
I was referred here by your electronics playlist. A really great explanation!
dude always helps me out but his voice is so soothing holy shit
Bro this guy teaches me more than my teacher and helps me more than my parents
As simple and understanding as always, thank you very much.
3:24 am exam at 8 pm, finished half of the studying with this guys help yet
1 - Spend one second
looking at the exercise.
2 - write it wrong.
3 - spent houres trying different increasingly complex methods to solve an impossible equation.
Wow please slow it down!!!!!!! Blew my mind
Your gonna help me pass ive been struggling with these
I like the video but the ones I do in school are way more complex and always come out to decimals which makes me so mad bro
Multiply by 100
Learning linear algebra, forgot about systems of equation so this helps!
I'm here again. Thanks for sharing it with us
thanks dude, you just saved my grade and I even speak diff language
I literally just watch this guy for every lesson
But why do you need to get rid of the y and why do you need to multiply one of the resulting equations by -1?
You have to get rid of one variable, in this case Y was just easier
And he multiplied following equations by -1 so they could subtract eachother rather than just add
Hope this helped
@@Mlmylji but why not -2 or -3
@@footballomegabecause it would not compute together I think( I am just a kid 😅)
Like if u did this (4x+3z=13)-2
(5x+3z=14)
It would come out like this
-8x-6z=-26
+ 5x +3z=14
--------
-3x-6z=-12
And so it would not have been able to subtract anything or delete any variable@footballomega
“A, B, and C have 2150 yen collectively. A has 120 yen more than B does. After C gives B 2/5ths of his money, B now has 220 yen more than A. How much money did A originally have?”
They say it's a problem that even middle schoolers can solve, but wow. Maybe I'm just dumb. I can't figure anything out.
(B+120) + B + C = 2150
An + (B+2/5C) + 3/5C = 2150
?
A = 710
B = 590
C = 850
A originally had 710 yen. The A, B, and C values are all BEFORE they gave money to each other.
I was able to gather the following equations from this problem.
A + B + C = 2150
A = B + 120
(2/5) C + B = A + 220
Now I will replace "A" with "B + 120".
(B + 120) + B + C = 2150
(2/5)C + B = B + 120 + 220
In the second equation, it looks like I can solve C since the B's cancel each other out.
(2/5)C + B = B + 120 + 220
(2/5)C = 340
C = 850
Using C, I can solve for B in the first equation.
(B + 120) + B + 850 = 2150
2B = 1180
B = 590
Now, I can use the very first equation I wrote and solve for A.
A + 850 + 590 = 2150
A = 710
I can now use the three original equations and check my work.
710 + 590 + 850 = 2150
710 = 590 + 120
(2/5)850 + 590 = 710 + 220
The above statements are true.
Unless you find that my original equations are incorrect, this is one way to solve.
To be fair in canada we don't do any of this till 9th or 10th but I just like being ahead
Thankyou God for this guy.
Why do you have to multiply the first equation by two and the one next to it by -1?
its still works if you didnt multiply em
The reason you have to multiply the first equation by 2 is so the Y’s cancel out. At first you’ll see that the first equation has y and the 3rd has -2y. Since we’re trying to cancel them out they have to have the same value with opposite signs, which would be 2y and -2y. After you multiply the 1st equation by two now the 1st equation has 2y, the 2nd equation still has -2y so they cancel out when you add. You would pretty much follow the same logic for the one that gets multiplied by -1, it’s to make it so one of the variables gets canceled out. Also, incase you were confused on this multiplying the whole thing doesn’t matter because it can still be divided by that same value to get the original equation. I hope this helped! :)
so you can just add the equations instead of subtracting them because subtracting isn't always accurate
Thank you so much for your help!
As always, thank u!
you are amazing bro keep up the amazing work
Thank you so much!
You the best 👍
your calculator sounds great😋😋😋😋
Very helpful!☺
2:39 why did u multiply by -1
So he multiplied by -1 because he want to do it more simpler so he can do it and also because subtracting is kind of confusing when you have a negative stacked on top of each other you can accidentally miss the sign and that will ruin the whole thing.
Example: 2x+y=7
11x+2y=20
------
2x+y=7(2)
11x+2y=20 -
------
4x+2y=14
11x+2y=20 -
--------
7x=7
x=1 ( I know this is wrong because the x is supposed to be negative because 4-11=-7)
So we sub the x=1 into prob 1
2+y=7
----
y=7-2
----
y=5
BUT if we do it the right way where x is equal to -1
2x+y=7
----
-2+y=7
----
y=7+2
----
Y=9
As you can see if we get the signs wrong on the first one that you solve it will become wrong for the entire thing
This took like 20 minutes
Thanks for this video it helped sooo much
My ONLY problem with this video is how he solved the first equation. I have on my paper a problem that can’t be solved with that second equation multiplication, so I need to have a different set of steps to complete it. This video only does something you can do in a specific group of situations, and doesn’t help when the 3 variable system of equations isn’t able to do that last elimination that you did. It would help many people to see how else you can solve a system without that last shortcut.
nice explanation keep it up bro
Actually solutions can be presented as { (1,2,3) }, representing the "set" of all possible solutions to the system. Since each equation represents a "plain ', three plains have only one point in common.
I LOVE YOU THANK YOU 🙏🙏🙏🙏
Best math guy
Thanks It helped me a lot
common the coefficients in order to compare and calculate
Thank you 😊
you're awesome!
THANKS MY FRIEND
you are good bro
THANK FOR HELP ME NOT FAIL ALGEBRA
Ok but you’re gonna fail English lol
THANK YOU
Thank you sir, you really saved me😂
How do ypu do it if there is only 2 equations?
Didn't wanna pay attention in class, I only listen to my boy tutor here
This is Top G status teaching. Keep it up!
youre always the man
Please help me sir a+b-c=-1...(1)
2a-2b+3c=8..... (2)
2a-b+2c=9..... (3)
Did you ever find the answers though
@@shanegilliam4896 I see someone else has a bad teacher this year
@@endgameisbad2733 lmao yup
@@shanegilliam4896 it do be like that sometimes
a=2, b=-1, c =2
But what can you do if the factors of the variables aren't constants so you can't cancel. For example:
x*sin a + y *sin b + z*sin c = 0
x*cos a + y*cos b + z*cos c =0
x*sin a * 2l + y*cos b * 3l + z* sin c * 4l = 0
be honest we’re all sophomores here struggling with algebra 2
Thank you
Is this substitution or elimination?
Why do you multiply by -1 and 2?
Following.
I got it ! He multiplied the first equation by 2 so that the 2y in equation 3 could be cancelled out.
Same applies to the 4th equation that was multiplied by -1
teacher i want more of these
At 1:45, why did you choose 2? It wasn't explained.
He used the third equation and he had to multiply by to so he could cancel z out
My problem is I don’t understand how your getting negative numbers to divide the equations by (5A+8b=6.55)(-7)
9a+7b=9.20 where does the -7 come from does it come from reversing the 7b?
I should not have taken college algebra before learning this stuff why didn’t anyone warn me i was told it was easier than algebra 1😭😭😭
1:42. How do you know when you need to multiply by 2?
When the variables do not have the correct number to cancel out prob
Pretty sure im a bit late, but it is because you would need to have two equations with only two variables to make this work, and he had chosen Y to be taken out, and the top equations Y was 1/2 of the third equations Y so to make them the same value so they cancel out, you have to multiply the whole top equation by 2 so when you add the first and third equations, the Y cancels out
Is this elimination by substitution?
I DONT UNDERSTAND, HOW ARE THE TWO NEW EQUATIONS GOING TO MAGICALLY CANCEL EACHOTHER OUT
you multiply one equation by a certain number to make a specific variable cancel out, like if one equation was : 2x+3y+2z = 25 : and the second equation was : 5x+7y-z = 25 : and you wanted z to cancel out, you multiply the entire second equation by 2 so -z could turn into -2z which cancels out the first equation's z which is positive 2z
@@ak09168 THANK YOU 🙏🏽
I got a math test in one hour, at 3:30 why do I multiply 5 by one?
1 was your x variable which he got in the first equation, in order to find z, he had to plug the x variable to the 5x. which makes it 5(1) aka 5 times 1, which really is just 5, but you still need to include that variable even if it’s just a 1.
When your teacher can’t teach so you watch this
Hello and welcome to whoever is taking electrical circuits and saying “I should’ve actually studied this well in high school” 💀
Whenever you hear this voice, just know that you are in the right place 🍻
How to know u need to + or - during counting??
I'm doing this online bc my fucking teacher decided not to finish her lesson on time and now I'm doing this
love you
his voice is still mesmerising
Doing this in ninth grade is a movie
???? huh?
What do you mean by movie? Nate??
I love you lol
_Luminaire_
Gayyyyyyyyyyyyyyyyyy
Jkjkjkjkjkjkjkjkjkjkjk chilllllllll bruh
But why multiplied by two? Is there a reason
x + y + z = 6
x + -2y + 3z = 1
x + 3y + -z = 8
ANS: X,Y,Z (1,3,2) Is my answer correct?
Yes u are correct
Probs from kumon math area
Where did you get -1 from ?
to cancel out 3z
For the first one, I would assume that x=1, y=2, and z=3!?
This does not work with equations ending with the same value
US education system never heard of Gauss? Just do the Gauß-Jordan algorithm, way easier and way way faster than this technique.
literally
Or heck just go with 1/|a|*adj(a) for a amtrix.
6:10 why negative 14
Negative 14 because -14 and +14 can cancel each other (elimination)
@@iHamza7 thank you for the explanation