因式分解 -x²y-4xy-4y

问题描述:

因式分解 -x²y-4xy-4y

-x²y-2xy-2xy-4y=-xy(x+2)-2y(x+2)=-y(x+2)²

-x²y-4xy-4y
=-y(x²+4x+4)
=-y(x+2)²