Answer
$30x^3+35x^2$
Work Step by Step
Distribute $4x^2$ to each term of the binomial to obtain:
$=5x^2(6x)+5x^2(7)$
Multiply the coefficients together then use the rule "$a^m \cdot a^n=a^{m+n}$" to the variables to obtain:
$=30x^{2+1} + 35x^2
\\=30x^3+35x^2$
