Question

If the coefficient of `x^3` in the expansion of `(2 + x)(3 - ax)^4` is 30, how do you find the values of the constant a?

Answer 1

`a=1`

Explanation:

Simply expand the expression and make it in the form of a polynomial
then you get the coefficient of `x^3` as `(54a^2-24a^3)` which is equal to 30
`54a^2-24a^3=30`
`a^2(54-24a)=30`
which gives `a=1`