x+二分之一的绝对值与y-3的平方互为相反数,求x2y-3xy-3x2y-2xy

分类: 作业答案 • 2021-11-20 10:27:51

问题描述：

x+二分之一的绝对值与y-3的平方互为相反数,求x2y-3xy-3x2y-2xy
如题

答

∵|x+1/2|+(y-3)²=0
绝对值大于=0
x=-1/2
y=3
x²y-3xy-3x²y-2xy
=-x²y-5xy
=-xy(x+5)
=3/2*4.5
=6.75