x^2+y^2=20 x^2-5xy+6y^2=0方程组：x^2+y^2=20 x^2-5xy+6y^2=0

2x^+xy-y^-4x+5y-6=? 诺x+y=6,xy=4 求(5x-4y-3xy)-(8x-y+2xy) 因式分解 x-xy+3y-3x 2x+xy-y-4x+5y-6 若x-y=5,xy=6,求x^2-xy^2和x^2y+xy^2 4xy-[(x²+5xy-y²)-(3xy-1/2y)]x=3,y=-6 x^2+xy+x=36,y^2+xy+y=20,求x+y. 若x+y=5,xy=6,求x^2y+xy^2的值 xy=6,x-y=5,x^2y+xy^2 5x^3y*(-3y)^2+(-6xy)^2*(-xy)+xy^3*(-4x^2) 1-2/x+y=xy,4y+6x=xy.求xy的解? 已知x>0,y>0,且x+6y=5根号xy,求(2x+根号xy-y)分之(x+根号xy+2y)的值 x+y=8,xy=-2,求(5xy+4x+7y)+(6x-3xy)-(4xy-3y)的值 x+y+xy=5 (x^2)y+x(y^2)=6 解方程组 6（x-y)-7(xy)=21,2(x-y)-5(x+y)=-1 图解(x+2y)(x+3y）=x平方+5xy+6y平方 √x(√x+2√y)=√y(6√x+5√y,求x-3√xy+2y/x+√xy-6y 已知2/X-1/Y=3,则(X-2Y-XY)/(5XY+6Y-3X)=? 已知2/x-1/y=3,则(2y-x+4xy)/(3x-6y-5xy)=?