问题
解答题
计算:(x-2y+2)(x+2y-2)
答案
(x-2y+2)(x+2y-2)
=[x-(2y-2)][x+(2y-2)]
=x2-(2y-2)2
=x2-(4y2-4y+4)
=x2-4y2+4y-4
计算:(x-2y+2)(x+2y-2)
(x-2y+2)(x+2y-2)
=[x-(2y-2)][x+(2y-2)]
=x2-(2y-2)2
=x2-(4y2-4y+4)
=x2-4y2+4y-4