Systems of equations with elimination (and manipulation) | High School Math | Khan Academy
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- เผยแพร่เมื่อ 20 ส.ค. 2024
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In some cases, we need to slightly manipulate a system of equations before we can solve it using the elimination method. So how it's done in this video. Created by Sal Khan.
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High School Math on Khan Academy: Did you realize that the word "algebra" comes from Arabic (just like "algorithm" and "al jazeera" and "Aladdin")? And what is so great about algebra anyway? This tutorial doesn't explore algebra so much as it introduces the history and ideas that underpin it.
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Finally, Khan Academy makes everything so much easier than hearing a math teacher in my school explain in some random gibberish and then ask us to do an example after 10 seconds and then the next day moving to some different lesson. This will totally save my grades, since I have a Math midterm exam on Friday
I am in 8th grade and we learned this this is going to help me a lot in my finals thanks so much your the best
you saved my grades
OMG! THANK YOU SOOOO MUCH
All the other tutorials were for adding and subracting and i taught thos were the only two ways you could do it and my exam is tommrow
THANK YOUUUUUU!!!!
*mAsSaGe* the equation
I still love that 😁
lol@@nocturnalvisionmusic
Its three am I have a math test today and I am ready to die
Dave The Pigeon has died
Lol mee tooo
Finals day.
Aaaaaaargh.
Did you pass
This is so helpful! My math teacher is a complete idiot!
I must agree
Definitely
The only idiot here is you by calling a person an idiot.
True, true...
I wrote this comment when I was 13 and it's still poppin lmfao
very helpful! you explained it better than my teacher ever could
Yes! You saved the day again Khan Academy! I dunno why I can't understand my Math teacher lol.
Ya if you add it you are right but he used subtraction that is why 5x - 15x gave him -10x but if you use addition it would give you a whole different answer so he made a mistake. I guess !!
Super helpful
omg i forgot i had this app and i was really struggling!!
Thank the lord for kan Academy!!👍👍
It would probably be easier to find either x or y for either equation and then just plug into the other equation.
Yeah he's also covered substitution in one of the previous videos. Think he's just showing other methods
You saved my life
You just saved me from a 0 on my homework
I love this man i would not be passing algebra with out him
THANK YOU!
Bro you are my math teacher
Is there any way to predict for which variable to solve first? Sometimes I need to solve complex circuits and I end up with three or four equations. However, it can sometimes be a bit difficult to choose the fastest path and trying out different paths takes some extra time, which isn't a very good thing.
Neither can mine. They need to get rid of MOST of the teachers and just use TH-cam for all the classes!
thank you so much for this homework help, i think i finally get it!!!
me watching sal solve the second equation by multiplying the top by 7 and the bottom by -5 and adding after I solved by adding the top and bottom after multiplying the top by 3/7 (I still got the right answer, but there were a lot more fractions)
What is the software that you use? I want to be able to do this on my own computer.
honestly i think this is just ms paint or something like that (yes i know this comment is 3 years old xD)
he says scratchpad a few times whatever that is
where this 20 by 4 came from in the second last step? if thats was from addition where this 15 by 4 again came from when they were added at the top??
This was really helpful. Thankyou!
@JonasM108 I did the same thing. It just so happens that in this problem, 5/4 is the answer for both x and y.
Thank you Khan
DAMN 'IT TH-cam an error occurred please try again later
thank you for posting this
thank you for the helpful vids
THANKS
your voice is like butter being rubbed against my ears.
Supah Doggeh bet you have diabetes now and horrible skin
Supah Doggeh lmao 😂
khan academy isnt it wrong
dont we need to get the coefficent of y for the 2nd equation as -10 since the coefficent of y in the 1st equation is -10 i dont know if i am right just telling
If the equations were subtracted you would be correct. -10y (-) -10y = 0. But the equations were 'added'. So -10y + 10y = 0.
.
thats a good point. not spam
Good evening, please kindly double check at 10:03 part, you said 3 X 5/4 is equal 15/4 , please correct it, it is 17/4 , by the way, thanks for great videos, I truly appreciate you.
what do I do with equations that start with a singular y for example y=2x-3 and the other one would be y=x+4
THANK YOU! 😺🙏
I dont get it..
thank you
What do I do if both are just y and x for example, -x+y=5?
For this you would just multiply the entire equation by -1:
-1 • (-x) + -1(y) = -1•5
Which would leave:
x-y = -5
Then solve as usual.
Three years later but I hope this helps anyone else :)
Happy Thanksgiving too (11/23/23)
@@nocturnalvisionmusic The video is solving systems of equations with the 'elimination' method. This viewer's question would need guidance on solving with the 'substitution' method. For example: [solve for x in terms of y] yields x=y+5
then solve for y with the new x identity [y+5+y=5] yields y=0, Now solve for x using this y value yields x = -5. So the original equation post substitutions would read: -(-5)+0=5 yielding 5=5. I too hope you had a Happy Thanksgiving!
And please excuse the turkey on my breath. 😊
@@jonwill that's a good explanation! Thank you too :)
Happy Thanksgiving 2023 to you :D
Thank you so muchhhh
I stg if there r fractions on my test tomorrow somebody is gonna get hurt
How would you solve this with y=4x+1 and x+y=15?
u take 4x to the left hand side and use substituition
Thanks bud, only 2 months late
i get it now!
Wow! This helped me so much!! Thanks for posting this~!
... The pretty colors helped, too. ^-^
Wouldn't subtracting -10y by +10 give you a -20
he's adding not sutracting
I understand
This is terribly confusing. I have some recollection of this from highschool where i was good at it and enjoyed it very much but the recollection of this does not help my understanding of it now.
I am more confused than ever. The fractions threw me off.
refresh
I’m watching this during my teachers office hours rn and she being so loud and I cant hear anything wtf-
salut les gens qui viennent d'euro
Thank You know online school doesn't mean staying up till midnight doing HW thank you I also proved my dad wrong 2! he thinks he knows it all... he only doesn't know one thing... he doesn't know all the crap in da world!!!!!
Shit*
I hear u
none of these videos help its not just this one its everyone one them im not saying there bad but my teachers just wants us to suffer
this video helps but at the same time it dose not you know what i mean
sorry for going on that rant this actually help its just that i have a hard time and finals are tomorrow
who invented this crap
Let's just hope they're long gone by now because I don't need anymore of this crap in my life.
Moon Goddess lol😁
Foreal
memes