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In the expansion of $(1 - 3x)^6 + (1 + ax)^5$, the coefficient of $x^3$ is $100$. Determine the value of 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: “Create an equation from the $x^3$ term in three parts, for example $(+/-)20\times3^3(x^3)$” …
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