Algebra: Linear equations 2 | Linear equations | Algebra I | Khan Academy
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Solving equations of the form AX+B=C
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Algebra I on Khan Academy: Algebra is the language through which we describe patterns. Think of it as a shorthand, of sorts. As opposed to having to do something over and over again, algebra gives you a simple way to express that repetitive process. It's also seen as a "gatekeeper" subject. Once you achieve an understanding of algebra, the higher-level math subjects become accessible to you. Without it, it's impossible to move forward. It's used by people with lots of different jobs, like carpentry, engineering, and fashion design. In these tutorials, we'll cover a lot of ground. Some of the topics include linear equations, linear inequalities, linear functions, systems of equations, factoring expressions, quadratic expressions, exponents, functions, and ratios.
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And how he got 10-9, since the LCD is 12 then what you do to the bottom you do to the top. 6x2=12 and 5x2=10.4x3=12 and 3x3=9. All of it turns to 10-9. Hope that helped lol.
Emerald Jerry thanks so much
God-tier comment.
Thankssssssss
alot
tysm
I joined a new school, had my half-yearly exams about 20 days after I joined, and now we're learning this. I would have asked my teacher to explain it better but my introverted self couldn't even if my life depended on it. Here I am, thank you Khan Academy.
Ik it’s hard to ask questions in class im also introverted just know it’s way better to ask questions in class than to be stuck and wait till you get home to understand it on youtube i was the same way honestly. if you have a question ask immediately before she goes on the next thing a couple of assholes would probably laugh but that’s only the first few times you ask dont let the kids bother you because most likely they are the ones not understanding it .its also helpful to the other kids that probably have the same questions . School is there for you to learn some kids don’t understand that asking questions is just the learning process its ok . I believe in you!
@@Ashleyscott27 since then, ive tried to communicate more with the teachers! thank you for your kind words, it genuinely means a lot
thumbs up if u look at this the day before the test.
God damn you are so right. I'm gonna fail anyway because I never did algebra in my life and they put me in anyway because this is the only level of math they had for my program. I'm screwed.
***** Man it calms me down so much to know that others are in the same boat as me. Don't worry though bro it's not going to be the end of the world if we fail or something. Good luck.
yup
omg dude same here lol did you guys make it?💪🏽
Thank you very much and keep pushing brother! *****
Me: "why won't you teach us something that will benefit us in life"
Teacher: "cause i get paid for it."
now im learning stuff before we get to it at school so i can make decent grades.
Smart
So did you get decent grades or nah
I'm glad we have the internet today because my teacher can't teach for shit
lol fr
same
school sucks hands down the internet is more effective
Arthur Fernandes Same. Whenever I swear I learn better from my friend who used to be worse than me compared to my teacher.
My teacher teaches us about numbers in grade 6
For those of you who are having trouble with 3:34. Assuming you understand how we got the 12; because 6*2 = 12 / 5*2 = 10 and because 4*3 = 12 / 3*3 = 9. What we do to the bottom we must do to the top.
To put it simply, you have to remember the rule whatever you do to the denominator you have to do to the numerator (and vice versa). So, 5/6 has to be multiplied by 2 to get 10/12 and 3/4 has to be multiplied by 3 to get 9/12. Since we need to subtract, the problem is 10-9/12. Hope it helped. :)
Here I am in quarantine, still struggling cause still my teacher can't explain anything 👌🏽
SAME LMAOOO
And I'm gonna need this in life when....?
Do u know now?
I love how you make me like fractions. Most teachers just make students avoid them, but you actually work with them and don't avoid them.
Im a 7th grader taking the 9th grade AQT test, and i swear to god, a real one finna fail😂im brushing up on all the standards right this minute. This 60 question quiz isn't gonna finish itself.
How'd you do?
brooo i remember that. you're doing it through Duke TIP?
for some steps he needs to explain why he is doing what he is doing a tad more
I was going to fail my online math class because I was behind... Because of you I have hope of passing! Thank you!
This video has better explanation the my teachers explanation! Thank you! I am now ready for the test tommorow!
did u pass?
why ive to learn this give me reason
to pass math class that why im learning it besides that theres no resone unless your going to be a scientist.
+tadios woldemeskel I suck at math myself, so I understand your question.
+That Guy and tadios woldemeskel Many jobs in the science and technology fields (which any more is where the vast majority of jobs are) require you to be able to perform math. So for things like Engineering, Computer Science, Architecture, Medicine, etc, you need math. It is not only scientists that need it nowadays. it sucks, but it is true.
There are still jobs that do not require (as much) math, such as journalism, and many business related jobs, law, etc.
can not figure out how he got 10-9 over 12
same
He found the lowest common denominator or the LCD of 6 and 4 which was 12 and then multiplied the sum so the bottom number would equal 12 on both equations. The reason you have to get both the numbers the same is because you can't add or subtract fractions that have different denominators, they have to be the same.
when you take away the fractions 5/6 - 3/4 u cant do it cuz the denominators are not the same u need to make them the same by multiplying u need to get the lowest common multiple so 6x2=12 and wat u do to the bottom u do to the top so it becomes 10/12 next is 4 times 3 wich is 12 thats why he put a 12 at the bottom because they both equal 12 well the denominators so again what u do to the bottom u do to the top so the fraction becomes 9/12 so then now u can subtract them . Rule - the denominator must be the same
memelashae101
Same!!!!
i agree!.. my teacher uses a vertical style and seeing it horizontally does give a new perspective!
8 years
12 years
14 years
DivineWisdom777, to subtract two fractions you have to find the common denominator. The smallest common denominator of 6 and 4 is 12. You get 12 by multiplying 6 by 2 (6x2=12), and 4 by 3 (4x3=12). If you change the denominator, you must change the numerator too of course. You have then to multiply each numerator by the same number you did the denominator. So you have to multiply 5 by 2 (5x2=10), and 3 by 3 (3x3=9). That is where 10 and 9 came from. I hope that helps.
i told you this in your last video keep being helpful!!
how did he get 9 from 1\12 + 3/4 ??? how did it end up at 1+9/12
My brain won't let me do the reciprocal unless I'm dealing with fractions. I don't know why, but it's reeeeallllly bugging me with him doing this xD
Just know reciprocals are the flipped version of a number. Ex 4 as a reciprocal is 1/4 5 is 1/5 10000 is 1/10000
I think that we should all say thank you to sal khan for his dedicaton and willingness to help others. Keep up the great work!!
D: hes awesome but my brain derped and i missed the whole video
Thanx Ivkaran sawhney!
If the coefficient (the number in front of the x) is a whole number, you divide. If the coefficient is dividing the x (i.e. x/3) you multiply.
When you want to add like terms on either side of an equation (x-3=5), you do the opposite operation of the sign in front of a term. So in that example, you would add the 3 (minus sign in front of the 3) to the 5 to get 8.
Hope that helped!
This is helpful! Thanks, im hoping for a good mark on my math test!
i'm about to take the SAT's after not doing algebra for 6 years, and so far i've gotten EVERY problem wrong at some point lol. i keep going, "oh right, you ADD both sides of the equal sign" or whatever.
thank god for khan!!! you're saving my life!!
on your website I wish you can relocate these linear functions before: unknown coefficients, variables, and variables with parentheses. I'm watching them now saying to myself " I wish he explained these earlier with this breakdown and detail" no worries though I learned the hard way and I think it helped even more cause now I'm destroying these particular problems so far. Thank you Khan Academy.
5:42
Find the hidden smiley face!
Found it
excellent teacher and I can't beleive he does this for no profit !
Thank you so much!
You should explain how you came up with the 1/12 plus 9/12 as a refresher or reminder.
Show the step, but it was still helpful.
Some might not know how you got there.
Thanks
Awesome help.
for subtraction u still use the lcm and do it like that, but for multplication and division u can do it like u described.
This is a sort of low level way to do this problem. Here is my way:
-1/2 + 3/4 = 5/6 . Then I would multiply the entire problem by 12 = LCM
Then you have all whole numbers, like how that works?
You get: -6x +9 = 10
-6x = 1
x = -1/6
Much easier.
I am a Algebra one student. THat is my war.
basically you got to put the +3 on the other side so it is -3 (our teacher taught us the magic tunnel) because it converts from a plus to a minus so 2x=-3-15 which is 2x=-18 so x=-9 so put the -9 back into the equation so it makes 2(-9)+3=-15 so 2 x -9= -18 then plus 3 and you get -15 which shows that 2x+3=-15 hope this helps?!
Over 12, to make its denometer are same. 5/6 times 2 = 10/12 and -3/4 times 3 = -9/12.
So 10/6 - 9/12 can write as (10-9)/12. Hope this can make you understand. Before can make fraction minus fraction, make sure its denometer are same. Thanks.
This video has better explanation the my teachers explanation! Thank you!
This was made a year before I was born and I'm watching it almost 14 years later
This video was made when I was only 2. 😝
@@6xmaaaa oh ok
This is really helpful.
this is one of the best
i love you because of you i'm a genius at every single math stage except calculus.
i lernt 1 ting witch is .......
the whole of algebra
i lik maths in all education cause of this khan guy he ROCKS!
١٥ سنه وللحين الوضع نفس ماكان نشوف اولادنا فالمتسقبل انشاء الله🤣
Adding a negative 3/4 is the same as subtracting a positive 3/4. Adding any negative value is the same as subtracting a positive value. You are doing the same operation.
He does this to isolate the variable x (you want your x's on one side, and your non-x's on another.)
Hopefully that helps, if not, let me know and I'll try to provide some more insight.
I'm confused about how you got 10-9 over 12 can someone help me? thanks
how did you get 10
Demi Latern he multiplied everything by 2
ok,,,
Problem: 4y - 4 + y + 24 = 6y + 20 = 4y
Solution: y=0
Problem: 5x + 3 = 2x + 15
Solution: x=4
My question is what route should I take to come up with each of those solutions? I need step by step, by step, by step instructions.
Please help. It's been a while.
i like the way you say let's do another problem
very simple !
i multiplied the 5/6 and -3/4 and simplifyed and still got 1/12?!?!?!?! i paused to work it out, then i saw u added and im like aww i got it wrong but i was like OMG btw ty for the help, my teachers never really taught me this stuff well, and well you a hero!!!!
What he did on the left side was add+
-3/4 to cancel out the positive 3/4.
Then what he did on the right is a bit confusing for me. He spoke 3:39 we have to do this addition fraction or subtraction fraction.
My question is could you do addition instead of the subtraction he did?
I understand where you got the half, and why you didn't just divide by 2, and you talk to much just walk us through the problems on how to solve them please thank you.
Margaret Dale the half came from the reciprocal of 2
Thank you very much kind sir.
3:34 i understand how you got the denominator 12 but i dont understand how you got 10-9 over 12. can you explain please?
I like the way you teach, thank you. I am getting it.
Thankyou so much this really helped me under stand it better especially the fractions.
Wow now I am starting to remember 2007. But this is good.
i wish u would explain a little more about why u do things..
Thank you!
yes thanks
Amazing indeed
Thanks for mentioning the video, it makes sense now.
hell yeah man! lol got a test tomorrow and had all week to study lol
khanacademy thanks a lot
Literally, Just Literally, this is the best math teacher ever. Also, this video came out a year after I was born lol, born in 2005. But this is the number 1 recommended source if you just started linear equations.
Just wait till you get into Polynomials...
Lengthy procedure
2x=-15
2X=-15-3= -18
Therefore X=-18/2= -9
*you divide 2 by -18 so its x= 2 divided by -18 so it is -9 and you can put it back into the equation to see if it is right
Nice hard scientist work🎉😂❤😅😮
this really helped me, thanks sir
THIS GUY IS AWESOME
THUNMBS UP IF U AGREE
THE WAY U TEACH IS AWESOME!!! THANKYOU!~!
this is the best video for help with math he's very easy to understand and put things in term someone can actually understand.
compared to all thesee other waste of time videos that get posted on youtube. hahahaha
Thank you :)
Good.
@LaurGrl1999 No, but if you want to pass and graduate then yes, you need it.
thanks a lot for the vid.
thank you this helped me a lot
This is easier than Linear Equations 1.
Because you are taking 3 from each side. Once you take 3 from the left side of the equation it no longer exists on that side.
Good for you. (no sarcasm)
Yup I’m failing my math test on Wednesday 😅😮
-3 and +3 when COMBINED =0 thats what u wanna do cancel everything so u get the variable alone and what u do to one side do to other
these youtube comments really helped on the 10,9 over 12
How do you decide which number to move specifically?
to add and subtract fractions, you need to find the lowest common denominator. because the lowest common denominator of 6 and 4 is 12, you must multiply the numerator by the same number that you multiplied the denominator by to get 12:
Numerator: 5*2=10
denominator: 6*2=12
get it? if not have mom or dad explain
its good
X can also be -20 for the first problem 🧐
This is so easy but always during a test I draw a blank, lol. Need to drill it into my skull.
Oh okay that explains a lot I was wondering what was up with the 12 and 10 and I thought he did it wrong. I can't hear the sound at the moment so that's why I got confused. and you can come up with any math problem and solve it right away however you want. All teachers mostly do that to make their own example in their own words.
wow this helped a lot!
For any future reference on how he got 10 and -9, the LCD is 12. 6 goes into 12 2times which is what is the same amount you would have to multiply 5. 4 goes into 12 3 times which once you multiply by -3=-9. For all of those struggling I feel EVERY bit of your pain. I hate math but sadly it's necessary for the diploma we're all chasing after :(
Why did lcm come into play in the first place ??
Thank You 🙏
Now I’ll pass my algebra exam
😃😜
review how to add and subtract fractions and you will understand
How did 5 over 6 becomes 10 please explain
Can u put up a video of Linear Systems( Isolate, Subsitute, Solve and Subsitute.) that kinda of stuff. Im a Freshman in highschool, so i need just a few levels higher than this.. could you please post???
2:07 its funny how how i just divided by 2 but you went all out on that problem.
I don't understand how at 3:50 it becomes 10 over 12 and -9 over 12, I get that the lowest common multiple between 4 and 6 is 12 but am unsure how he got 10 and -9 over the 12, is it because he doubled 5 and tripled -3 to get 10 and -9 respectively so as to get the numbers as close to 12 as possible or was there another reason?
@kingpalash
12/6=2*5=10
12/4=3*3=9
i hope u got it
@sharpsh00ter123
Agreed. Most people dont even care
@TheMujee thanks i was just thinking about this...
i was 2 months old when he published this video