Ok so I know that this is problem realllly easy, but nevertheless..

the family of functions is y = ce^(-2x) + e^(-x)

the solution of the equation is y' + 2y = e^(-x)

I have to find the constant c which defines the solution which also satisfies the initial condition y(-3)=10

now i started out finding y' and then plug in the initial condition...

I'm getting stuck. Any help??