Equations with Several Variables

If there is more than one variable, enter the Variable(s) to Solve for in the dialog box that appears when you choose Exact from the Solve submenu.

$\blacktriangleright$ Solve + Exact

${\dfrac{{1}}{{x}}}$ + ${\dfrac{{1}}{{y}}}$ = 1 (Enter x), Solution is : $\left\{\vphantom{ x=-\dfrac{y}{1-y}}\right.$x = - ${\dfrac{{y}}{{1-y}}}$$\left.\vphantom{ x=-\dfrac{y}{1-y}}\right\}$

${\dfrac{{1}}{{y}}}$ + ${\dfrac{{1}}{{z}}}$ + ${\dfrac{{1}}{{x}}}$ = 1 (Enter z), Solution is : $\left\{\vphantom{ z=-\dfrac{yx}{x+y-yx}}\right.$z = - ${\dfrac{{yx}}{{x+y-yx}}}$$\left.\vphantom{ z=-\dfrac{yx}{x+y-yx}}\right\}$

${\dfrac{{1}}{{r_{1}}}}$ + ${\dfrac{{1}}{{r_{2}}}}$ = ${\dfrac{{1}}{{R}}}$ (Enter R), Solution is : $\left\{\vphantom{ R=\dfrac{r_{1}r_{2}}{r_{1}+r_{2}}}\right.$R = ${\dfrac{{r_{1}r_{2}}}{{r_{1}+r_{2}}}}$$\left.\vphantom{ R=\dfrac{r_{1}r_{2}}{r_{1}+r_{2}}}\right\}$