C1: (x^2+2xy+y^2):(x+y)=
a,x-y b,x+y c,x+2y d,2x+y
C2: (x^2-y^2):(x-y)=
a,x+y b,(x-y)^2 c,x-y d,(x+y)^2
C3: x^2-(2y)^2=
a,x^2-2y^2 b,x^2+2y^2
c,(x-2y)(x+2y) d,(x+2y)(x=2y)
C4: (2x+y)(2x-y)=
a,4x-y b,4x+y c,4x^2-y^2 d,4x^2+y^2
C5: 6xy(2x^2-3y)=
a,12x^2y+18xy^2 b,12x^3y-18xy^2
c,12x^3y+18xy^2 d,12x^2y-18xy^2
thank kiu so veri mac