计算(8x-7y)(7y+8x)-(7x+8y)(7x-8y)

分类: 作业答案 • 2021-12-20 01:29:34

问题描述：

答

=56xy+64x^2-49y^2-56xy-（49x^2-56xy+56xy-64y^2）
=64x^2-49y^2-49x^2+64y^2
=15x^2+15y^2

答

128x^2-98y^2

答

(8x-7y)(7y+8x)-(7x+8y)(7x-8y)
=64x²-49y²-49x²+64y²
=15x²+15y²
=15(x²+y²)

答

(8x-7y)(7y+8x)-(7x+8y)(7x-8y)
=56xy+64x^2-49y^2-56xy-49x^2+56xy-56xy+64y^2
=15x^2+15y^2