## Intermediate Algebra for College Students (7th Edition)

$f=\displaystyle \frac{pq}{p+q}$
Get rid of fractions (multiply with LCD=pqf) $qf+pf=pq\qquad$ ... factor out f $f(q+p)=pq\qquad$ ... divide with $(q+p)$ to isolate f $f=\displaystyle \frac{pq}{p+q}$