6y+12/y^2+4y+4 -y^2-4/y^2-4y+4 +y^2/y^2-4
2个回答

6y+12/y^2+4y+4 -y^2-4/y^2-4y+4 +y^2/y^2-4

=6(y+2)/(y+2)^2-(y+2)(y-2)/(y-2)^2+y^2/(y-2)(y+2)

=6/(y+2)+(y+2)/(y-2)+y^2/(y-2)(y+2)

=6(y-2)/(y-2)(y+2)+(y+2)(y-2)/(y-2)(y+2)+y^2/(y-2)(y+2)

=(6y-2+y^2-4+y^2)/(y-2)(y+2)

=(2y^2+6y-6)/(y-2)(y+2)