计算(8x-7y)(7y+8x)-(7x+8y)(7x-8y)
问题描述:
计算(8x-7y)(7y+8x)-(7x+8y)(7x-8y)
答
(8x-7y)(7y+8x)-(7x+8y)(7x-8y)
=64x²-49y²-49x²+64y²
=15x²+15y²
=15(x²+y²)