Answer
$x^3+11x^2+28x$.
Work Step by Step
The given expression is
$=(x+4)(x^2+7x)$
Distribute $(x^2+7x)$ to each term of $(x+4)$.
$=x(x^2+7x)+4(x^2+7x)$
Use distributive property.
$=x(x^2)+x(7x)+4(x^2)+4(7x)$
Multiply.
$=x^3+7x^2+4x^2+28x$
Combine like terms.
$=x^3+11x^2+28x$
Hence, the product is $x^3+11x^2+28x$.
