Question

Let $(1+ax)(1-2x)^{3}=\sum_{n=0}^{4}a_{n}x^{n}$, where $a$ is a constant. If $a_{2}=0$, then the value of $a$ is

• A. 1
• B. 9
• C. 3
• D. 5
• E. 2

Hint:

Logic Tip: When asked for a specific coefficient in a product of polynomials, you don't need to expand the entire expression. Only calculate the specific combinations of terms that multiply to give the desired power of $x$.

Answer 1

Answer: (E)