Solve the literal equation for a. y=x(ab/a-b)

We are asked to solve y=x((ab)/(a-b)) for a:
Here is one method:
Multiply both sides by (a-b) to clear the fraction:
y(a-b)=x(ab)
Use the distributive property to clear the parantheses:
ya-yb=xab
Subtract xab from both sides; add yb to both sides. (This gets all terms with a on the left side of the equation, while all other terms are on the right hand side.)
ya-xab=yb
Factor out the common a on the left side:
a(y-xb)=yb
Divide both sides by (y-xb):
a=(yb)/(y-xb)
This is the solution. You have successfully solved the equation for a.