原式=(x﹣y)(x+y) 2﹣xy(x﹣y)﹣(x﹣y) 3﹣xy(x﹣y)﹣2xy(x﹣y)+3x 2
=(x﹣y)(x+y) 2﹣4xy(x﹣y)﹣(x﹣y) 3+3x 2
=(x﹣y)[(x+y) 2﹣4xy﹣(x﹣y) 2]+3x 2
=3x 2,
与y无关,所以y抄错不影响答案.
原式=(x﹣y)(x+y) 2﹣xy(x﹣y)﹣(x﹣y) 3﹣xy(x﹣y)﹣2xy(x﹣y)+3x 2
=(x﹣y)(x+y) 2﹣4xy(x﹣y)﹣(x﹣y) 3+3x 2
=(x﹣y)[(x+y) 2﹣4xy﹣(x﹣y) 2]+3x 2
=3x 2,
与y无关,所以y抄错不影响答案.