6given:
2x + y = 0
x – y = 6
what is the solution to the system of equations?
a (1, -2)
b (2, -4)
c (4, -2)
d (5, -1)

2x + y = 0 (first equation)
x - y = 6 (second equation)

2x + y = 0 (first equation)
2x - 2y = 12 (second equation multiplied by 2 so that the x is the same)

3y = -12 (second equation subtracted from first to find y)
y = -4 (-12 divided by 3 to find y)

2x - 4 = 0 (y substituted into equation)

2x = 4 (-4 moved to other side so we can isolate 2x)

x = 2 (4 divided by 2 to find x)

The answer is (2, -4), as we worked out that x is 2, and y is -4. 

x=20

Step-by-step explanation:

4x +10 = 90

-10 from both sides

that gives you 4x=80

80 divided by 4 gives you 20=x