Chapter 3 - Polynomial and Rational Functions - Exercise Set 3.7 - Page 430: 19

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

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