x/625-0.2=xy/9800 y=?

多元函数极限lim sin(xy)/x (x.y) -> (0.2) = lim {[sin(xy) / xy ] * （-3x^y+2xy)-( )=4x^+xy X²+2xy+y²/xy乘x²-2xy+y²/xy+y²= 已知x-xy=8,xy-y=-9,求x+y-2xy的值 解方程x*x+xy=y+y*y 已知x-y=4xy，则2x+3xy-2yx-2xy-y 已知xy>0,证明xy+xy/1+x/y+y/x>=4 由已知x+y=-2,xy=3那么2(x+xy)-[(xy-3y)-x]-(-xy)等于多少? 1\x+1\y=8\x+y,则y\xy+x\xy=? x^2+xy+x=36,y^2+xy+y=20,求x+y. 如果x^2+xy+y-14,y^@+xy+x=28,求x+y的值. X+y=3 xy=-5 Xy=?