JAMB 1994 · UME · Q16

Expressions, formulae & change of subject

Find $P$ if $\dfrac{x - 3}{(1 - x)(x + 2)} = \dfrac{P}{1 - x} + \dfrac{Q}{x + 2}$ .

Worked solution (try it first)

Multiply through by $(1 - x)(x + 2)$ : $x - 3 = P(x + 2) + Q(1 - x)$ .
Put $x = 1$ so the $Q$ term vanishes: $1 - 3 = 3P$ , so $-2 = 3P$ .
So $P = -\frac23$ , option A.

Report a problem with this question