Question

если 1/a=1/b+1/c то с =?

Answer 1

$\frac{1}{a} = \frac{1}{b} + \frac{1}{c}$

$\frac{1}{a} - \frac{1}{b}=\frac{1}{c}$

$\frac{b-a}{ab}=\frac{1}{c}$

$c(b-a)= ab$

$c= \frac{ab}{b-a}$