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