若:x*2+y*2=1,则(1+xy)(1-xy)有无:最小值和最大值.及得数

若x-y=4,xy=1,则(2x+y-2xy)-(3x+2y+xy)-(4xy+3y-5x)= 已知x+y=1,xy=-2,则x²y+xy²-2xy 若1/x-1/y=2,求3x-2xy-3y/x-xy-y的值3x-2xy-3y/x-xy-y 不好意思，是3x-2xy-3y/x-2xy-y 若x-y=1,xy=5,则x^2y-xy^2＝ 若1/X-1/Y=3,则2X+XY-2Y/X-2XY-Y=? 若x/1-y/1=5,则x-2xy-y/2x+5xy-2y=? 若(2x-14xy-2y)除以(x-2xy-y)=4,则1/x-1/y= 若1/x+1/y=2,则(2x-xy+2y)÷(3x+5xy+3y) 若x+y=10 xy=-1 则x²+y²=(x+y)²-2xy= 若1/x-1/y=2,则（3x+xy-3y)/(x-xy-y）的值为? 已知xy/x+y=1/2,则代数式3x-5xy+3y/-x+3xy-y= 若x-y=4,xy=1,求(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 若2x方+2xy+y^2-2x+1=0,则xy= 若x+y=1,x不等于0则x+(2xy+y^2)/x/(x+y)/x= 已知x+y=1,xy=1/5,则x^2y=xy^2 若xy满足x²+2x+y-2√y-1=-1,求xy, 若x,y满足x^+2y^-2xy+1=0,求xy的值 x^=2-xy y^=1-xy 则x^-y^ 多少啊