已知x²+y²=5,xy=2,求(2x²+xy+3y²)-(x²-xy+2y²)的值
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/30 15:49:14
![已知x²+y²=5,xy=2,求(2x²+xy+3y²)-(x²-xy+2y²)的值](/uploads/image/z/5266055-47-5.jpg?t=%E5%B7%B2%E7%9F%A5x%26%23178%3B%2By%26%23178%3B%3D5%2Cxy%3D2%2C%E6%B1%82%EF%BC%882x%26%23178%3B%2Bxy%2B3y%26%23178%3B%29-%28x%26%23178%3B-xy%2B2y%26%23178%3B%29%E7%9A%84%E5%80%BC)
已知x²+y²=5,xy=2,求(2x²+xy+3y²)-(x²-xy+2y²)的值
已知x²+y²=5,xy=2,求(2x²+xy+3y²)-(x²-xy+2y²)的值
已知x²+y²=5,xy=2,求(2x²+xy+3y²)-(x²-xy+2y²)的值
原式=2x²+xy+3y²-x²+xy-2y²
=(x²+y²)+2xy
=5+4
=9
原式=2x²+xy+3y²-x²+xy-2y²
=2(x²+y²)+y²+xy-x²+xy-2y²
=2(x²+y²)-(x²+y²)+2xy
=(x²+y²)+2xy=5+4=9