# 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?

$a = 1$
then you get the coefficient of ${x}^{3}$ as $\left(54 {a}^{2} - 24 {a}^{3}\right)$ which is equal to 30
$54 {a}^{2} - 24 {a}^{3} = 30$
${a}^{2} \left(54 - 24 a\right) = 30$
which gives $a = 1$