Question

x-10y=30 7y-8x=52

Answer 1

x-10y=30 => x = 30 + 10y -(1)
7y-8x=52 -(2)
Sub. (1) into (2)
7y-8 (30+10y) =52
7y - 240 - 80y = 52
-73y = 292
y = -4

Put y = -4 into (1)
x = 30 + 10 (-4) = ... ?

Answer 2

x-10y=30-----------(1)
7y-8x=52-----------(2)

(1)*8 + (2),
-71y=292
.'. y=-4

apply y=-4 into (1),
.'. x=-10