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For the expansion of $(k + \frac{1}{3}x)^5$, the coefficient of $x^2$ is $30$. Determine the value of the constant $k$.
Mathematics 9709 · AS & A Level · Series
Series — practice question
Worked solution & mark scheme
This 3-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Use $k^3 \times \left(\frac{1}{3}x\right)^2 \times 10$, or an equally valid correct factorisation” …
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