x+y=32x+3y=8求XY

x+y=32x+3y=8求XY 已知1/x+1/y=8,求2x-3xy+2y/x+2xy+y的值 y'+xy=x^3求微分 已知3x*+xy-2y*=0,求(x/y)-(y/x)-(x*+y*)/(xy)的值.*是平方 已知(x+y):y=8:3,求2x+5y/3x-y和x^2-xy/y^2+3xy的值 x>1,y>0,且满足xy=x^y,x/y=x^3y,求x+y 已知x-xy=8,xy-y=-9,求x+y-2xy的值 已知xy=-2,x-y=3,求（x+y)（x-y)-y^2+（x-y)^2-（6x^2y-2xy^2)÷2y 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3x^2+xy-2y^2=0,求{(x+y)/(x-y)+4xy/(y^2-x^2)}/{(x+3y)*(x-y)} x+y=8,xy=-2,求(5xy+4x+7y)+(6x-3xy)-(4xy-3y)的值