(2X-Y)方-4(X-2Y)(X+2Y)

问题描述:

(2X-Y)方-4(X-2Y)(X+2Y)

(2X-Y)方-4(X-2Y)(X+2Y)
=4x^2-4xy+y^2-4(x^2-4y^2)
=4x^2-4xy+y^2-4x^2+16y^2
=17y^2-4xy