Chapter 3 - Polynomial and Rational Functions - Exercise Set 3.7 - Page 430: 17

$x=kz(y+w)$ $y=\displaystyle \frac{x}{kz}-w$

$x$ varies directly as $z:\qquad x=kz$ $x$ varies directly as $(y+w):\qquad x=k(y+w)$ Combined (jointly): $\qquad x=kz(y+w)$ Solving for $y,$ $x=kz(y+w)\qquad/\div kz$ $\displaystyle \frac{x}{kz}=y+w\qquad/-w$ $y=\displaystyle \frac{x}{kz}-w$