作业帮4xy-[(x²+5xy-y²)-(x²+3xy-2y²)],其中x=2,y=-1求值，化简
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/08 17:15:06
![4xy-[(x²+5xy-y²)-(x²+3xy-2y²)],其中x=2,y=-1求值，化简](/uploads/image/z/7645096-64-6.jpg?t=4xy-%5B%28x%26%23178%3B%2B5xy-y%26%23178%3B%29-%28x%26%23178%3B%2B3xy-2y%26%23178%3B%29%5D%2C%E5%85%B6%E4%B8%ADx%3D2%2Cy%3D-1%E6%B1%82%E5%80%BC%EF%BC%8C%E5%8C%96%E7%AE%80)
4xy-[(x²+5xy-y²)-(x²+3xy-2y²)],其中x=2,y=-1求值，化简
4xy-[(x²+5xy-y²)-(x²+3xy-2y²)],其中x=2,y=-1
求值，化简
4xy-[(x²+5xy-y²)-(x²+3xy-2y²)],其中x=2,y=-1求值，化简
4xy-[(x²+5xy-y²)-(x²+3xy-2y²)]
=4xy-(x²+5xy-y²-x²-3xy+2y²)
=4xy-(2xy+y²)
=2xy-y²
=(2x-y)y
=(2x2+1)x(-1)
=-5
15151515
4xy-[(x²+5xy-y²)-(x²+3xy-2y²)]
=4xy-(x²+5xy-y²-x²-3xy+2y²)
=4xy-(2xy+y²)
=4xy-2xy-y²
=2xy-y²
=y(2x-y)
=(-1)x(2x2+1)
=-5