Question

a-5b=7 aflati x din relatia x-123+5a-25b=137

Answer 1

$x-123+5(a-5b)=137 \\ x-123+5*7=137 \\ x=137+123-35 \\ x=225$

Answer 2

a-5b=7⇒5a-25b=35
x-123+35=137
x+35=260
x=225