已知x^2-xy=60´xy-y^2=40,求代数式x^2-y^2和x^2.-2xy+y^2的值
来源:学生作业帮 编辑:拍题作业网作业帮 分类:数学作业 时间:2024/04/30 01:15:04
已知x^2-xy=60´xy-y^2=40,求代数式x^2-y^2和x^2.-2xy+y^2的值
∵x²-xy=60;xy-y²=40.
x(x-y)=60;y(x-y)=40
x-y=60/x; y*60/x=40
y/x=2/3
y=2/3x;x=3/2y
x²-xy=60
x²-2/3x²=60
1/3x²=60
x²=180
xy-y²=40
3/2y²-y²=40
1/2y²=40
y²=80
x²-y²=180-80=100
x²-2xy+y²=(x-y)²=(60/x)²=360/x²=360/180=2
x(x-y)=60;y(x-y)=40
x-y=60/x; y*60/x=40
y/x=2/3
y=2/3x;x=3/2y
x²-xy=60
x²-2/3x²=60
1/3x²=60
x²=180
xy-y²=40
3/2y²-y²=40
1/2y²=40
y²=80
x²-y²=180-80=100
x²-2xy+y²=(x-y)²=(60/x)²=360/x²=360/180=2
已知:x-xy=40,xy-y=-20,求代数式x-y和x+y-2xy的值.
已知x^2-xy=60´xy-y^2=40,求代数式x^2-y^2和x^2.-2xy+y^2的值
已知x^2-xy=60´xy-y^2=40,求代数式x^2-y^2和x^2.-2xy+y^2的
已知xy/x+y=2,求代数式3x-5xy+3y/-x+2xy-y的值
已知x-y=2xy,求代数式3x-5xy-3y/x+xy-y的值
已知xy/x+y=2,求代数式3x-xy+3y/-x+3xy-y的值
已知x^2-xy=60,xy-y^2=40,求代数式x^2-y^2和2x^2-5xy+3y^2的值
已知x^2-xy=60,xy-y^2=40,求代数式x^2-y^2和x^-2xy+y^2的值
已知x+y=-1,xy=-2,求代数式-5(x+y)+(x-y)+x(xy+y)的值
已知y=3+xy,求代数式2x+3xy-2y/x-2xy-y的值.
已知x—xy=40,xy—y=—20,求代数式x—y和x+y—2xy的值
已知x+y=-1,xy=-2,求代数式-5(x+y)+(x-y)+2(xy+y)的值