(-x-y)(x+y)和(-x-y)(x-y)的答案,最好是用完全平方差的公式.今天就要啊!
问题描述:
(-x-y)(x+y)和(-x-y)(x-y)的答案,最好是用完全平方差的公式.今天就要啊!
答
(-x-y)(x+y)
=-(x+y)²
=-x²-2xy-y²
(-x-y)(x-y)
=(-y-x)(-y+x)
=(-y)²-x²
=y²-x²