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

Logarithmic and exponential functions — practice question

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

Determine the value of $a$.

(ii)[3]

Using this value of $a$, factorise $p(x)$ in full.

(iii)[2]

Hence, solve the equation $p(e^y)=0$ and give the answer 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: Substitute $x=2$, set equal to zero and proceed to solve

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