Mathematics 9709 · AS & A Level · Series

Series — practice question

(main)[5]

The coefficient of $x^3$ in $(a + x)^5 + (2 - x)^6$ is $90$. Determine the value of the positive constant $a$.

Worked solution & mark scheme

This 5-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Coefficient of $x^3$ in $(a+x)^5$ stated as $10a^2$” …

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