若x+y=-6,xy=2.75,求x-y的值 这题怎么算啊快点回复、要过程!谢谢啦~

若x+y=6,xy=2.75,x-y>0,求x-y的值 若x^2+xy+y=14,y^2+xy+x=28,求x+y 若x+y=5,xy=6,求x^2y+xy^2的值 若正实数x,y满足2x+y+6=xy,求xy的最小值. 若正实数X,Y满足2X+Y+6=XY,求XY的最小值. 若x+y=4,x-y=6,求xy(y^2+y)-y^2(xy+2x)-3xy的值. 若x-y=5,xy=6,求x^2-xy^2和x^2y+xy^2 若x+y=4 x-y=6 求xy(x^2+y)-y^2(xy+2x)-3xy的值求值 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 |x|/x+y/|y|+xy/|xy|= 1-2/x+y=xy,4y+6x=xy.求xy的解? 已知x+y=6,xy=7,试求x*x+y*y,x*x-y*y的值 已知xy=-2,x-y=3,求（x+y)（x-y)-y^2+（x-y)^2-（6x^2y-2xy^2)÷2y 若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y*y)的值 已知x的平方+y的平方-8x+6y+25=0,求(x-y+4xy/x-y)(x+y-4xy/x+y) 已知x²+y²-8x+6y+25=0,求（x-y+4xy/x-y）（x+y-4xy/x+y） 1/x-1/y=x,求5y+xy-5y/y-xy-x=? 诺x+y=6,xy=4 求(5x-4y-3xy)-(8x-y+2xy)