(x-y+1)y'=1 求通解

我们老师只是提示了下 用dx对dy 反着做,我也没听懂

已知(x*x+y*y)(x*x+y*y-1)=12,求x*x+y*y的值 x+y+(x-y)*3+1=? 实数x,y满足|x-y+1|+|x+y-2007|=0,{-x\y}= x+2y=2x+y+1=7x-y 求：2x-y? 3(x+y)-2(x-y)=9 5(x+y)+2(x-y)=-1 设x-y=1,则y*y*y+3xy-x*x*x为多少 1/4(x+y)+1/2(x+y)*(x+y)>=x*根号y+y*根号x (x-y+1)y'=1 求通解 y=f(1/x),求y'' 方程IN(1+x+y)=1+xy确定了函数y=y(x),则y'(0)=?