Question

x+7y=-14
-2x+14y=0
Solve by elimination.

Answer 1

needhelp?

Answer 2

the key to elimination is that you want to be able to cancel out one variable from each of the equations.

x+7y=-14
-2x+14y=0

none of the terms added together will cancel out... for example:
x + (-2x)= -x ****you want this to equal 0

or
7y+14y= 21y ******does not equal to 0

so we must multiply one equation so that we can do that!


let's multiply the first equation by 2 and see what can cancel out...

2(x+7y) = 2(-14) ~~~ 2x+14y= -28

now we have these 2 equations

2x+14y=-28
-2x+14y=0

now add the equations together
we get: 28y= -28 (the x will cancel out and you end up with what y will equal!)

y=-1

now we plug this -1 into any of the 2 equations in order to get our x value :)

Answer 3

thank you, that helped me some^_^