已知1/x+1/y=4,求4x-2xy+4y/x+3xy+y的值
已知:x-y=1,xy=-2.求:(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值
.已知:x-y=1,xy=-2.求:(-2xy+2 x+3y)-(3xy+2y-2x)-(x+4y+xy)的值
已知1/x-1/y=3,求(3x+4xy-3y)/(x-2xy-y)的值
已知1/x+1/y=3,求3x-4xy+3y/(x+2xy+y)的值
已知x-y=4xy,求x-2xy-y分之2x+3xy-2y的值!
若x-y=4,xy=1,求(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值
x-y=1,xy=2.求:(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值
已知|3-y|+|x+y|=0,求[2(x+y)-3(xy+4)]÷1/xy的值.
已知1/x-1/y=4,求2x+xy-2y/x-2xy-y的值
已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值?
已知x+y=3,xy=1,求代数式5xy+4x+7y+6x-3xy-4xy+3y的值.
已知x=y+1,求x^4-xy^3-x^3y+3x^2y-3xy^2+y^4的值