Question

m^2*n^2-m*n^3= ?
7x^2y^3-21x^3y^3= ?
m*(m+2)-4*(m+2)= ?

Answer 1

m^2*n^2-m*n^3=mn^2(m-n)
7x^2y^3-21x^3y^3=7x^2y^3(1-3x)
m*(m+2)-4*(m+2)=m^2+2m-4m+8=m^2-2m+8

Answer 2

1) =(mn)^2-mn^3=mn^2(m-n)
2) =7x^2y^3(1-3x)
3) =(m+2)(m-4)