Question

Which ordered pair is the solution to the system of equations?

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

A.
(−3, −2)

B.
(−1, 3)

C.
(1, 5)

D.
(−4, 0)

Answer 1

So,

I have decided to use Elimination by Addition.

Add the two equations together
3x = -12

Divide both sides by 3
x = -4

Substitute -4 for x in the second equation.
-4 - y = -4

Add 4 to both sides
-y = 0
y = 0

Check
2(-4) + 0 = -8
-8 = -8 This checks.

-4 - 0 = -4
-4 = -4 This also checks.

The solution set for this system is as follows:
S = {(-4,0)}

That would be option D.

Answer 2

so first solve for x and y
add the 2 equations together

2x+x+y-y=-8-4
3x=-12
divide by 3
x=-4
subsitute
-4-y=-4
addd 4 to both sdies
-y=0

the solution is (x,y) (-4,0) or D