20.
(-4x)^2
You need to distribute the power of 2 to -4 and x
21.
([3m/2n])^3
You need to distribute the power of 3 to 3,m,2, and n.
22.
-(xy^2)^3
Distribute the 3 to x and y. When distributing a power and a power you will multiply, thus y^2 will equal y^6. Don't forget the negative outside the parenthesis.
