X+Y=50 XY=616 求XY

X+Y=50 XY=616 求XY |x|/x+y/|y|+xy/|xy|= sin(xy)=x 求dx/dysec(xy)-y ]/x 还是 x/[sec(xy)-y] 3X^2+XY+Y=15 求XY. 如果xy+x+y=6,试求自然数 xy 已知x-xy=8,xy-y=-9,求x+y-2xy的值 1-2/x+y=xy,4y+6x=xy.求xy的解? 当x-y=2xy时,求4x-3xy-4y/xy y/x=ln(xy) 求dy/dx(xy-y^2)/(xy+x^2) 已知xy^2=-2,求-xy（x^2y^5-xy^3-y)的值. 已知xy^2=-2 求-xy(x^2y^5-xy^3-y) xy^2-e^x+e^y=1 求y' 是xy^2 不是xy xy^2=-3,求-xy(x^2y^5-xy^3-y) 已知x+y=12,xy=9,求(x+3xy+y)/(xy+xy)的值 已知x^2-xy=5,xy-y^2=-3求3(x^2-xy)-xy+y^2 已知x^-xy=5,xy-y^=-3,求式子3(x^-xy)-xy+y^的值 已知x:y=3:2,求(x²+3xy)/(xy+2xy) xy'=x-y求方程通解