1.X+Y=5,X-Y=－2,则X²+Y²的值是多少?

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 已知x*x+4x+y*y-2y+5=0,则x*x+y*y=? 若(X×X+Y×Y)(X×X+Y×Y-5)=36,则X×X+Y×Y＝ 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 1.y=x^5+5^x+x^x+lgx 2.y=xe^x^2求y'' 3.已知y=e^f(x),则y''= 4.已知y=(1+x)^x,求导数y' 若3x-5y=0,则x+y/x=（）,x-y/y=（）,2x-3y/2x+3y=( ) 1.X+Y=5,X-Y=－2,则X²+Y²的值是多少? （5x-6y)(x+y)=0(x不等于y),则y/x= 设f(x+y,x-y)=x^2-y^2,则f(x,y)= 若f(x+y,y/x)=x^2-y^2,则F(X,Y)= 已知f(x+y,y/x)=x^2-y^2,则f(x,y)= x*x+2x+y*y-4y+5=0 x= y= x+y/2+x-y/6=5 2(x+y)-3(x-y)=-2 解方程组(x+y)(x-2y)=-5 (x-y)(x+2y)=7 3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 已知x/5=y/3,则(x/x+y)+(y/x-y)-(yxy/xxx-yxy) 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27