已知|x+y+2|+(2x-3y-1)的平方=0,则4x的平方-5xy+y的立方=

2025-06-29 13:26:08
推荐回答(3个)
回答1:

|x+y+2|+(2x-3y-1)²=0
因为|x+y+2|≥0,(2x-3y-1)²≥0,要使等式成立,则|x+y+2|=0且(2x-3y-1)²=0
即x+y+2=0,2x-3y-1=0
x+y+2=0,····①
2x-3y-1=0····②
解:①*2-②,得,y=-1代入①,得x=-1
所以x=-1,y=-1
4x²-5xy+y³=4×(-1)²-5×(-1)×(-1)+(-1)³=4-5-1=-2

回答2:

x+y+2=0
2x-3y-1=0
x=-1,y=-1
4x^2-5xy+y^3
=4-5-1=-2

回答3:

x+y+2=0
2x-3y-1=0