A.y=y1(x)+ B.y=y1(x)+c C.y=y1(x)++c D.y=y1(x)+c
A.y=cy1(x)+y2(x) B.y=y1(x)+c2y2(x) C.y=c[y1(x)+y2(x)] D.y=c1y(x)-y2(x)
A.(xey-2y)dy+eydx=0 B.xy′+y=ex+y C.[x/(1+y)]dx-[y/(1+x)]dy=0 D.dy/dx=(x+y)/(x-y)