Question

Which ordered pair is the solution to the system of equations?
x+y=4
x-y=-6
A.
(2, 2)

B.
(1, −7)

C.
(−1, 5)

D.
(−2, 4)

Answer 1

sum both equations:

2x = -2
x = -1
x - y = -6
-1 -y = -6
y = 5
solution set as (x, y) = (-1 , 5)

Answer 2

You could also just plug in each set and check which will verify both of the equations , but that's just waste of time.

x + 4 = -1 + 5 = 4
x - y = -1 -5 = -6