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In $(4 + ax)\left(1 + \frac{x}{2}\right)^6$, the coefficient of $x^2$ is $3$. Determine the constant $a$.
Mathematics 9709 · AS & A Level · Series
Series — practice question
Worked solution & mark scheme
This 4-mark question has a full step-by-step worked solution and mark scheme. One marking point: “A correct expansion that gives $\frac{6x}{2}$ or $15 \times \frac{x^2}{3}$” …
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