JAMB 2010 · UTME · Q40

If $y = (2x + 1)^3$ , find $\dfrac{dy}{dx}$ .

Worked solution (try it first)

Chain rule: bring down the power 3 and reduce it by one, giving $3(2x + 1)^2$ .
Multiply by the derivative of the inside, $2x + 1$ , which is 2: $\frac{dy}{dx} = 6(2x + 1)^2$ , option D.