Answer:
r = [tex]\frac{2}{2su-v}[/tex]
Step-by-step explanation:
given
su = [tex]\frac{1}{r}[/tex] + [tex]\frac{v}{2}[/tex]
multiply through by 2r to clear the fractions
2rsu = 2 + vr ( subtract vr from both sides )
2rsu - vr = 2 ← factor out r from each term on the left side
r(2su - v) = 2 ← divide both sides by (2su - v )
r = [tex]\frac{2}{2su-v}[/tex]