JAMB 2012 · UTME · Q11

Make $n$ the subject of the formula $w = \dfrac{v(2 + cn)}{1 - cn}$ .

Worked solution (try it first)

Multiply both sides by $1 - cn$ and expand: $w - wcn = 2v + vcn$ .
Collect the $n$ terms on the right and the rest on the left: $w - 2v = vcn + wcn$ , so $w - 2v = cn(v + w)$ .
Divide by $c(v + w)$ : $n = \frac1c\left(\dfrac{w - 2v}{v + w}\right)$ , option A.