Question

3x+8y=-5

-2x+2y=18
Solving systems of equations and inequalities
Solving systems by elimination

Answer 1

(-7,2)

Explanation:

3x+8y=-5

-2x+2y=18

so first of all, you want either x or y to be the same for both equations (it can be negative or positive but has to be the same number)

to do that, we'll multiply them:

I'll do y because it is easier

(-2x+2y=18) 4

-8x+8y=72

3x+8y=-5

the y's now match

let's subtract them because they're both positive

-8x - 3x = -11x

8y - 8y = 0

72 - (-5) = 77

so -11x = 77

which results to x = -7

now we need the y.

to do that, we simply plug in the x in any of the equations:

-2x+2y=18

-2 (-7) + 2y = 18

14 + 2y = 18

2y = 4

y = 2

so the answer is (-7,2) if you're looking for a point