How do you solve the system of equations x- 3y = - 12 and - 3x + 4y = 16 by elimination?

1 Answer
Dec 11, 2016

x=0, y=4

Explanation:

x-3y=-12, if you add 3y to both sides, the left side cancels out, and you get one variable's value: x=-12+3y

Now plug that in for x in the second equation.
-3(-12+3y)+4y=16

Simplify.
36-9y+4y=16
36-5y=16
-5y=-20
y=4

Getting y, we plug that into the equation for x in order to find x.
x=-12+3(4)=-12+12=0

Plugging into the first equation to check variables...
0-3(4)\stackrel{?}{=}-12
-12=-12