Answer :
ok so remember
if xy=0, assume that x and y=0 so
z(z+2)(z-1)=0
assume each factor equals zero
z=0
z+2=0
z=-2
z-1=0
z=1
z=-2, 0, and/or 1
if xy=0, assume that x and y=0 so
z(z+2)(z-1)=0
assume each factor equals zero
z=0
z+2=0
z=-2
z-1=0
z=1
z=-2, 0, and/or 1