The solution is

y(t) = a*e^t + b*e^(5t)

where "a" and "b" are constants that depend on the values of the initial conditions

a = y'(0) - 5b

y(t) = a*e^t + b*e^(5t)

where "a" and "b" are constants that depend on the values of the initial conditions

**.**b = (y''(0) - y'(0))/20a = y'(0) - 5b