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Calculate the coefficient of $x^3$ in the binomial expansion of $(3 + x)\sqrt{1 + 4x}$.
Mathematics 9709 · AS & A Level · Algebra
Algebra — practice question
Worked solution & mark scheme
This 4-mark question has a full step-by-step worked solution and mark scheme. One marking point: “State the uncombined $x^3$ term (or its coefficient) in the expansion of $\sqrt{1+4x}$.” …
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