已知(x+y)^2=11 (x-y)^2=5 求x^2+y^2和xy
已知(x+2)^2+|x+y+5|=0,求3x^2y-[2x^2y-(2xy-x^2y)-4x^2]-xy
已知x+y=-1,xy=-2,求代数式-5(x+y)+(x-y)+x(xy+y)的值
已知xy=2,x-y=3,求(x+y)(x-y)-y^2-(6x^2y-2xy^2)/2y的值.
已知xy=-2,x-y=3,求(x+y)(x-y)-y平方+(x-y)平方-(6x2y-2xy平方)/2y的值
已知x^2+xy-2y^2=0 (x不等于0,y不等于0),求x/y-y/x-(x^2+y^2)/xy的值
初中数学分式已知x/y=2,求(x*x-xy+3y*y)/x*x+xy+6y*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):y=8:3,求2x+5y/3x-y和x^2-xy/y^2+3xy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^2+y^2-4x+6y+13=0求(xy+y^2/5x^2-5xy+xy+y^2)·(5/x+y)-(y/x-y
已知x,y>0 2x+y+3=xy 求5x+4y最小值
已知xy^2=-6,求-xy(x^3y^7-3x^2y^5-y)的值