the problem:
Suppose at time zero, the bob was drawn upward four units from the equilibrium position, let C=2, K=2, m=1 lbm, initial speed=2 unit/sec find an expression for body's position.

and in the solution it says: y''+6y'+5y=0
my question is: from where does the numbers (6) and (5) that is in te above DE came from ?
2. Relevant equations
spring equation:
my''+cy'+ky=f(t)
consider f(t) =0

3. The attempt at a solution
stopped at first because of the first step