Question

9x + y = 0
18x + 4y = –8

Answer 1

What we trying to do dessie91?

Answer 2

You can either use substitution or elimination here.
Substitution:
y=-9x
18x+4(-9x)=-8
-18x=-8
x=4/9
9x+y=0
9(4/9)+y=0
4+y=0
y=-4

For elimination:
(9x+y=0) <---Multiply this by -2 to eliminate x and solve for y
18x+4y=-8

-18x-2y=0
18x+4y=-8

Add these equations together; you get:
2y=-8
y=-4
Plug -4 back into an equation and solve for x:
9x-4=0
9x=4
x=4/9