Odpowiedź:
1/p=1/q-1/r
1/r= 1/q-1/p
1/r= (p-q) / pq /*r
1= r (p-q) /pq /*pq
r( p-q)=pq /: p-q
r= pq/(p-q)
Szczegółowe wyjaśnienie:
[tex]\frac{1}{p} = \frac{1}{q}-\frac{1}{r}\\\\\frac{1}{r} = \frac{1}{q}-\frac{1}{p}\\\\\frac{1}{r} = \frac{p}{pq}-\frac{q}{pq}\\\\\frac{1}{r} = \frac{p-q}{pq}\\\\\boxed{r = \frac{pq}{p-q}}[/tex]
