已知x+y=2000 x-y=0.005 求x^2-y^2-200x+200y的值

分类: 作业答案 • 2022-06-03 09:56:20

问题描述：

答

x^2-y^2-200x+200y
=(x-y)(x+y)-200(x-y)
=(x-y)(x+y-200)
=0.005*(2000-200)
=0.005*1800
=9