已知(a+b)²=7,(a-b)²=3,求(1)x²+y² (2)xy的值
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/24 00:31:12
![已知(a+b)²=7,(a-b)²=3,求(1)x²+y² (2)xy的值](/uploads/image/z/754006-22-6.jpg?t=%E5%B7%B2%E7%9F%A5%EF%BC%88a%2Bb%EF%BC%89%26%23178%3B%3D7%2C%EF%BC%88a-b%EF%BC%89%26%23178%3B%3D3%2C%E6%B1%82%EF%BC%881%EF%BC%89x%26%23178%3B%2By%26%23178%3B+%EF%BC%882%EF%BC%89xy%E7%9A%84%E5%80%BC)
已知(a+b)²=7,(a-b)²=3,求(1)x²+y² (2)xy的值
已知(a+b)²=7,(a-b)²=3,求(1)x²+y² (2)xy的值
已知(a+b)²=7,(a-b)²=3,求(1)x²+y² (2)xy的值
(x+y)²=7,(1)
(x-y)²=3,(2)
(1)+(2)
2(x²+y²)=10
x²+y²=5
(1)-(2)
4xy=4
xy=1
(1)x²+y²=5;(2)xy=1.