First solve the characteristic equation r^2 + 8r + 16=0.
The general solution is y=Ae^(r_1x) + Be^(r_2x),
where r_1 and r_2 are the two solutions to the characteristic eqn, and A and B are constants.
Except that in this case, you have only one solution, cause r^2 + 8r + 16 is a perfect...