WAEC 2020 · Paper 1 · Q12

If $V = P\log_X(M + N)$ , express $N$ in terms of $X$ , $P$ , $M$ and $V$ .

Worked solution (try it first)

Divide both sides by $P$ : $\log_X(M + N) = \dfrac{V}{P}$ .
Change to index form ( $\log_X a = b$ means $a = X^b$ ): $M + N = X^{\frac{V}{P}}$ .
Subtract $M$ : $N = X^{\frac{V}{P}} - M$ , option A.