Mathematics 9709 · AS & A Level · Logarithmic and exponential functions

Logarithmic and exponential functions — practice question

The polynomial $p(x)$ is given by $p(x) = ax^3 + ax^2 - 15x - 18$, with $a$ a constant. It is stated that $(x - 2)$ is a factor of $p(x)$.
(i)[2]

Determine the value of $a$.

(ii)[3]

With this value of $a$, factorise $p(x)$ fully.

(iii)[2]

Hence solve $p(e^y) = 0$, giving the answer correct to 2 significant figures.

Worked solution & mark scheme

This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: Insert $x=2$, set the result to zero and try to solve

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