已知|xy-2/3|+(y+1)平方=0,求x-2(xy+1/3y平方)-(3/2-2/3y平方)的值
来源：学生作业帮助网 编辑：六六作业网 时间：2024/11/29 04:54:12
已知|xy-2/3|+(y+1)平方=0,求x-2(xy+1/3y平方)-(3/2-2/3y平方)的值
已知|xy-2/3|+(y+1)平方=0,求x-2(xy+1/3y平方)-(3/2-2/3y平方)的值
已知|xy-2/3|+(y+1)平方=0,求x-2(xy+1/3y平方)-(3/2-2/3y平方)的值
|xy-2/3|+(y+1)平方=0
xy-2/3=0
y+1=0
x=-2/3
y=-1
x-2(xy+1/3y平方)-(3/2-2/3y平方)
=x-2xy-2/3y平方-3/2+2/3y平方
=x-2xy-3/2
=-2/3-4/3+3/2
=-1/2
|xy-2/3|+(y+1)平方=0
|xy-2/3|=0，(y+1)平方=0
y+1=0
xy-2/3=0
y=-1
-x-2/3=0
x=-2/3
x-2(xy+1/3y平方)-(3/2-2/3y平方)
=x-2xy-2/3y平方-3/2+2/3y平方
=x-2xy+2/3y平方-2/3y平方-3/2
=x-2xy-3/2
=-2/3-2*(-2/3)*(-1)-3/2
=-2/3-4/3-3/2
=-2-3/2
=-7/2
xy=2/3,y=-1,所以x=-2/3
-2/3-2(2/3+1/3)-(3/2-2/3)=-7/2
|xy-2/3|+(y+1)^2=0 => xy=2/3 ;y=-1 => x=-2/3
=> x -2(xy+ 1/3y^2) -(3/2 -2/3y^2)=x-2(-x)-3/2 +2/3 =3x-3/2+2/3=-2-3/2+2/3=7/6
∵|xy-2/3|≥0
(y+1)²≥0
又∵|xy-2/3|+(y+1)²=0
∴|xy-2/3|=0
(y+1)²=0
∴y=-1
x=-2/3
∴x-2(xy+1/3y平方)-(3/2-2/3y平方)
=-2/3-2(2/3+1/4)-(3/2-1)
=-2-2+1
=-3