(x-y+1)dy/dx=1dx/dy = x-y +1dx/dy -x = -y+1letxg= Ae^yxp= By +Cxp' =Bxp' -xp = -y+1B-(By +C) = -y +1-By +(B-C) = -y +1B=1 and B-C=1B=1 and C=0xg=y通解x= xg+xp =Ae^y +y