Question

5x-10y=-40 solve for y

Answer 1

\[5x-10y=-40\]we need to get y on one side so whats something you can remove from the side containing y? :)

Answer 2

5x?

Answer 3

yes so lets subtract 5x from both sides :)\[~~~5x-10y=-40\]\[\underline{-5x~~~~~~~~~~~~~~-5x}\]\[~~~~~~~-10y=-40-5x\]
so now we have \(-10y=-40-5x\)

Answer 4

\(y\) is still no alone...what can we do?

Answer 5

divide?

Answer 6

by?

Answer 7

-5x?

Answer 8

?...no, try again

Answer 9

-40

Answer 10

nope -10

Answer 11

we need to make the equation look like "\(y=~...\)" so yes we would divide by -10:\[\underline{\cancel{-10}^1y}=\underline{\cancel{-40}^4}~~\cancel{-\underline{~~5~}}^1x\]\[\cancel{-10}^1~~~~~~\cancel{-10}^1~~~~\cancel{-10}^2\]\[{1y\over1}={4\over1}-{1x\over2}\]which is written as:\[y=4+{x\over2}\]

Answer 12

lets say you have equation \(ax+by=c\), where \(a\) and \(b\) are coefficients and \(c\) is a constant
and we are asked to solve for \(y\)

to do so we must first get rid of all the terms around the term containing the y, so we would do this:\[ax+by=c\]subtract \(ax\) from both sides:\[by=c-ax\]the \(y\) is still not alone so we will next divide by its coefficient \(b\) to get \(y\) alone:\[by=c-ax\]divide both sides by \(b\):\[y={c\over b}-{ax\over b}\]
i hope this better explains things :)

Answer 13

this is a very helpful video..watch it, you'll probably understand it better :)
http://www.youtube.com/watch?v=JPERkt9Ad48

Answer 14

thanks

Answer 15

yw.