for
y'' + 2y'+ 1y=0 solving for y
and let y=emt
therefore
m2+2m+3=0 (differentiating y and multiplying out e^mt
which is
(m+1)2=0
m=-1
NOTE: We didnt take e^mt because there is no value of m such can bring an answer equal to zero
y=Ae-t+Bte-t
for
y'' + 3y'+ 2y=0 solving for y...