Question

w(r + y) = D;solve for w

Answer 1

divide both sides by (r+y)
$\frac{w(r+y)}{r+y}=\frac{d}{r+y}$
$(w)(\frac{r+y}{r+y})=\frac{d}{r+y}$
$(w)(1)=\frac{d}{r+y}$
$w=\frac{d}{r+y}$