solue the followring disiential equations by heibnit linear egalation method. ci)(-x) dy (i) dy - xy = 1 de X +y Cos x I+ Sn n de Gii ) (-x) dy + 2 xy = x V1-x2 Civ) + 2xy = 2e?? dx V) dr +(2r ot 8 + Sin 20) de =o