已知x+y=6,xy=7,试求x*x+y*y,x*x-y*y的值

已知x+y=6,xy=7,试求x*x+y*y,x*x-y*y的值 已知X+y=6,xy=7 求x^2y+xy^2=已知X+y=6,xy=7 x^2y+xy^2 已知x=3y,试求（x-y)^2+2xy-y^2/x^2+7xy+y^2 已知x=3y,试求(x-y)^2+2xy-y^2/x^2+7xy+y^2 已知:x/y=-2,求x^2-2xy-3y^2/x^-6xy 已知(1/x)-(1/y)=5,求(6x+7xy-6y)/(8y-9xy-8y) 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） 已知xy=-2,x-y=3,求（x+y)（x-y)-y^2+（x-y)^2-（6x^2y-2xy^2)÷2y 已知xy/x+y=6,求3x-2xy+3y/-x+3xy-y的值. 已知(xy)/(x+y)=6求(3x-2xy+3y)/(-x+3xy-y)的值. 已知x+y=3,xy=6,.求根号x/y+根号y/x 帮个忙啦 已知x+y=-6 xy=8 求√y/x+√x/y 已知x*x+xy-2y*y=7 求整数x y的值 已知x^2-6xy+9y^2=0,求(x-y)/(x+y) 已知X+Y=6,xy=3求代数式（5XY+4X+7Y)+(6X-3XY)-(4XY-3Y)的值 已知x+y=3,xy=1,求代数式5xy+4x+7y+6x-3xy-4xy+3y的值. 已知x+xy=-3,xy+y=7,试求x+2Xy+y的值