> 数学 >
已知x+y=3,xy=-2,求x^3+y^3的值
fast!
人气:136 ℃ 时间:2020-01-14 17:46:32
解答
x^3+y^3
=(x+y)(x²-xy+y²)
=(x+y)[(x+y)²-3xy]
=3×(3²+6)
=45
推荐
猜你喜欢
© 2026 79432.Com All Rights Reserved.
电脑版|手机版