Mathematics 9709 · AS & A Level · Series

Series — practice question

In the expansion of $(x + a)^6$, the coefficient of $x^4$ is $p$, and in the expansion of $(ax + 3)^4$, the coefficient of $x^2$ is $q$. You are told that $p + q = 276$.
(main)[4]

Find the values that the constant $a$ can take.

Worked solution & mark scheme

This 4-mark question has a full step-by-step worked solution and mark scheme. One marking point: “The coefficient of $x^4$ is correctly given by $p=15a^2$” …

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