Answer :

2x = 4y
x = (4y)/2
x = 2y

8x = - 2y - 10
8(2y) = -2y - 10
16y + 2y = -10
18 y = -10
y = -10/18
y = -5/9

So, how x = 2y
x = 2 (-5/9)
x = -10/9