Answer
$x=kyz$
$y=\displaystyle \frac{x}{kz}$
Work Step by Step
$x$ varies directly as $y:\qquad x=ky$
$x$ varies directly as $z:\qquad x=kz$
Combined (jointly): $\qquad x=kyz$
Solving for $y,$
divide both sides by ($kz)$
$\displaystyle \frac{x}{kz}=y$
