Solve for r in the following equation (frac{1}{r – 1}) + (frac{2}{r + 1}) = (frac{3}{r})

A.
3 
B.
4 
C.
5 
D.
6
Correct Answer: Option A
Explanation
(frac{1}{r – 1}) + (frac{2}{r + 1}) = (frac{3}{r})
Multiply through by r(r 1) which is the LCM
= (r)(r + 1) + 2(r)(r – 1)
= 3(r – 1)(r + 1)
= r^{2} + r + 2r^{2} – 2r
3r^{2} – 3 = 3r^{2}
r = 3r^{2} – 3
r = 3
∴ r = 3