What is the product of 4xy and y2 + 2x?
4xy 3 + 4xy
4xy 2 + 8x 2y
4xy 3 + 8x 2
4xy 3 + 8x 2y

The product of 4xy and y² + 2x can also be written as
4xy(y² + 2x)

When we have brackets like this, we multiply whatever is left of the brackets by everything inside.

1) 4xy multiplied by y²
    4xy x y² = 4xy³

2) 4xy multiplied by 2x
    4xy x 2x = 8x²y

3) Add together 4xy³ and 8x²y 
    4xy³ + 8x²y

Letter b hope it