xy满足(x+y)^2=1/4,xy=-1/2,求下列个数的值.（1）（x^2+1)(y^2+1) (2)x^4+y^4 (3)x^2-y^2 (4)x^6+y^6

若xy满足x²+2x+y-2√y-1=-1,求xy, 正数x,y满足(1+x)(1+y)=2,求xy+1/xy最小值 若正数xy满足x+4y=1,（x+y）/xy最小值 若x,y满足x^+2y^-2xy+1=0,求xy的值 已知实数xy满足x²﹢y²-xy+2x-y+1=0求xy 已知正数x,y满足(1+x)(1+2y)=2,则4xy+1/xy的最小值是多少? 如果有理数x y 满足|x-1|+|xy-2|=0,求xy的绝对值 1-2/x+y=xy,4y+6x=xy.求xy的解? 已知A=5x^+2xy-4y^,B=-x^-4xy+y^,C=x^-xy+3y^其中xy满足|2x+1|+(y-4)^=0,就A-2B+C已知A=5x^+2xy-4y^,B=-x^-4xy+y^,C=x^-xy+3y^其中xy满足|2x+1|+（y-4)^=0,求A-2B+C-2B+C的值 已知,xy满足y²=-x²+2x-5/4-y,代数式xy/x+y= 已知1/x-1/y=2,求3x+7xy-3y/2x-3xy-2y答案是1/x-1/y=2(y-x)/xy=2 得：x-y=-2xy(3x+7xy-3y)/(2x-3xy-2y)=[3(x-y)+7xy]/[2(x-y)-3xy]=(-6xy+7xy)/(-4xy-3xy)=xy/(-7xy)=-1/7 谁能帮我解释一下=[3(x-y)+7xy]/[2(x-y)-3xy]=(-6xy+7xy)/(-4xy-3xy) 是怎 X、Y满足XY=K,xy是什么关系? X、Y满足XY=K,xy是什么关系? 已知实数xy,满足10x²-2xy+y²+6x+1=0,求x+y 先化简再求值3(2x^2y-xy^2)-(5x^2-4xy^2)其中x y 满足|x+2|+(y-1/2)=0 已知xy满足约束条件y=2 2X+y 已知实数x、y满足xy>0,且8/xy+1/x+1/y=1, 若正数xy满足x+y=xy,则x+4y的最小值