How do you solve the system of equations x+ 2y = - 4 and 2y - x = - 8?

2 Answers
Jun 21, 2017

x=2, y=-3

Explanation:

Here we have a system of two linear equations.

x+2y =-4 [A]

2y-x=-8 -> -x+2y =-8 [B]

[A] + [B] -> 4y =-12

y=-12/4 = -3

Replacing for y in [A]

x+2xx(-3) =-4

x=-4+6 = +2

Check result in [B]

2xx(-3)-2 = -6-2 = -8

Results are correct.

Jun 21, 2017

(2,-3)

Explanation:

x+2y=-4
2y-x=-8

We can use the elimination method to isolate a variable. In this case, we'll start off with isolating y.

Add the two equations together.

x+2y=-4
-x +2y=-8

4y=-12

You can now solve this new equation for y.

y=-3

Plug the value for y back into one of the original equations.

x+2(-3)=-4
x-6=-4

x=2

Your solution is (2,-3).