6(x-y)-7(xy)=21,2(x-y)-5(x+y)=-1
1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y)
已知x+y=-1,xy=-2,求代数式-5(x+y)+(x-y)+x(xy+y)的值
已知1/x-1/y=5 求分式-x+xy+y/2x+7xy-2y
已知1/x-1/y=5,求分式y+xy-x/2x+7xy-2y的值.
已知1/X-1/y=5,求分式(y+xy-x)/(2x+7xy-2y)的值
1/x-1/y=5求(-x+xy+y)/(2x+7xy-2y)
已知x+y=-1,xy=-2,求代数式-5(x+y)+(x-y)+2(xy+y)的值
已知X+Y=-1,xy=-2,求代数式-5(x+y)+(x-y)+(xy+y)的值
已知xy/x+y=1/2,则代数式3x-5xy+3y/-x+3xy-y=
若x+y=-1,则x^4+5x^3y+x^2y+8x^2y^2+xy^2+5xy^3+y^4=( )
√x(√x+2√y)=√y(6√x+5√y,求x-3√xy+2y/x+√xy-6y
已知x-y=3xy,且xy不等于0,则-3x+6xy+3y/(7x-5y)-9xy-(3x-y)