A rectangle has a height of 4 and a width of x^3+3x^2+2x

What are you trying to find? The area of the rectangle?

Step-by-step explanation:

Area of rectangle is height x width

So you multiply 4 by (X^3 + 3X^2 + 2X)

You multiply only the coefficients

So you get

4X^3 + 12X^2 + 8X