(main)[3]
In the expansion of $(2 + ax)^7$, the coefficients of $x$ and $x^2$ are equal. Determine the value of the non-zero constant $a$.
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: “Combinations used with cancellation: ${}^7C_1 \times 2^6 \times a = {}^7C_2 \times 2^5 \times a^2$” …
- Full mark scheme, point by point
- Step-by-step worked solution
- Write your answer & get it marked instantly by AI