WAEC 2025 · Paper 1 · Q16✱✱

Solve $3x^2 + 25x - 18 = 0$ .

Worked solution (try it first)

Find two numbers with product $3 \times (-18) = -54$ and sum 25: they are 27 and $-2$ .
Split and group: $3x^2 + 27x - 2x - 18 = 3x(x + 9) - 2(x + 9)$
$= (3x - 2)(x + 9)$ .
So $x = \frac23$ or $x = -9$ , option B.