JAMB 2011 · UTME · Q12✱✱

Make $R$ the subject of the formula $T = \dfrac{KR^2 + M}{3}$ .

Worked solution (try it first)

Multiply both sides by 3: $3T = KR^2 + M$ .
Subtract $M$ : $KR^2 = 3T - M$ , then divide by $K$ : $R^2 = \frac{3T - M}{K}$ .
Take the square root: $R = \sqrt{\dfrac{3T - M}{K}}$ , option D.