xy=(x-10)(y+1) xy=(x-15)(y+3) 解方程组.

|x|/x+y/|y|+xy/|xy|= 已知x+y=1,xy=-2,则x²y+xy²-2xy 1-2/x+y=xy,4y+6x=xy.求xy的解? 已知xy>0,证明xy+xy/1+x/y+y/x>=4 xy>0,证xy+1/xy+x/y+y/x>=4 1*{x+y+xy=7{x2+y2+xy=132*{x2+y2=10{x+xy+y=7 [(xy+2)(xy-2)-2x^2y^2+4]/xy,其中x=10,y=-1/25 [(xy+2)(xy-2)-2x^2y^2+4]/xy,其中x=10,y=-1/25 xy=(x-10)(y+1) xy=(x-15)(y+3) 解方程组. -1/3x²y²+xy=( )(xy-3) -xy-3/1y平方+(x平方=3xy) 【 】-【X平方+3XY】=-XY-1/3Y平方 ( )-(x^2+3xy)=-xy-1/3y^2 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 先化简,再求值：x^x+xy/x^x-xy^(y^y-xy/xy)除以(x+y),其中x=1/3,y=-3 1/x-1/y=x,求5y+xy-5y/y-xy-x=? 计算：( 根号xy-xy/x+根号xy)÷根号xy-y/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