若x-y=5,xy=6,则xy-xy是多少

若x-y=5,xy=6,则xy-xy是多少 若xy/x+y=2,则3x-5xy+3y/-x+3xy-y=?/是分之 若|x|/y+y/|y|=0,则|xy|/xy=?是：若|x|/x+y/|y|=0，则|xy|/xy=？ 若x-y=5,xy=6,则x的平方y-xy的平方的值是? 若x-y=4,xy=1,则(2x+y-2xy)-(3x+2y+xy)-(4xy+3y-5x)= 已知x-y=3xy,且xy不等于0,则-3x+6xy+3y/(7x-5y)-9xy-(3x-y) 若x-y=5,xy=6,求x^2-xy^2和x^2y+xy^2 |x|/x+y/|y|+xy/|xy|= 正数x,y满足2x+y+6=xy,则xy的最小值是 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 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 若正实数x,y满足2x+y+6=xy,则xy的最小值是?答案是18, 3xy+xy+3+4xy-7化简,已知x=5,y=6 若 x+y=5,xy=-50 则x^2y+xy^2 =( ) 若x-y=1,xy=5,则x^2y-xy^2＝ 若x+y=5,xy=6,求x^2y+xy^2的值 若x+y=0,xy=-6则x^3y+xy^3的值是(请写过程) 若x+y=5,xy=4,则式子2分之xy-2x-2y的值是