> 数学 >
设x(x-1)-(x²-y)=-2 ,求(x²+y²)/2-xy的值
人气:481 ℃ 时间:2020-06-25 10:01:56
解答
x(x-1)-(x²-y)=-2
x²-x-x²+y=-2
x-y=2
(x²+y²)/2-xy=(x²+y²-2xy)/2
=(x-y)²/2
=2
推荐
猜你喜欢
© 2024 79432.Com All Rights Reserved.
电脑版|手机版