WAEC 2022 · Paper 1 · Q6

Indices & standard form

If $4^{3x} = 16^{x + 1}$ , find the value of $x$ .

Worked solution (try it first)

Write 16 as $4^2$ : $16^{x + 1} = 4^{2(x + 1)} = 4^{2x + 2}$ .
The bases match, so $3x = 2x + 2$ .
Subtract $2x$ : $x = 2$ , option B.

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