[tex]y(a-b)=c(y+a)\ \ \ \ \ |\text{use distributive property}\\\\ya-yb=cy+ca\ \ \ \ |-cy\\\\ay-by-cy=ac\\\\(a-b-c)y=ac\ \ \ \ \ |:(a-b-c)\neq0\\\\\boxed{y=\dfrac{ac}{a-b-c}}[/tex]
