已知(x-2)²+|y+1| =0,A=5x²+3xy-4y²,B=x²+2xy-2y²,求:A-2B的值
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/05 15:34:19
![已知(x-2)²+|y+1| =0,A=5x²+3xy-4y²,B=x²+2xy-2y²,求:A-2B的值](/uploads/image/z/1333371-3-1.jpg?t=%E5%B7%B2%E7%9F%A5%EF%BC%88x-2%EF%BC%89%26%23178%3B%2B%7Cy%2B1%7C+%3D0%2CA%3D5x%26%23178%3B%2B3xy-4y%26%23178%3B%2CB%3Dx%26%23178%3B%2B2xy-2y%26%23178%3B%2C%E6%B1%82%EF%BC%9AA-2B%E7%9A%84%E5%80%BC)
已知(x-2)²+|y+1| =0,A=5x²+3xy-4y²,B=x²+2xy-2y²,求:A-2B的值
已知(x-2)²+|y+1| =0,A=5x²+3xy-4y²,B=x²+2xy-2y²,求:A-2B的值
已知(x-2)²+|y+1| =0,A=5x²+3xy-4y²,B=x²+2xy-2y²,求:A-2B的值
因为两个同时大于等于零的项相加等于零,则每一项等于零.所以x=2,y=-1.
所以求得A=10 B=-2
所以A-2B=14
(朋友,我不会在电脑上输入平方啊立方啊的符号,只能用文字表达了.)