## simplifying a nonhomogeneous recurrence relation

I'm sorry if this seems like a simple question, but can someone show me step by step, how this equation
$\displaystyle 2^{n+2}C(n+2) - 9*2^{n+1}C(n+1) + 14*2^nCn = 2^n$
simplifies to -10C = 1

Thanks
I am understanding substituting Vn into the equation, but I have a problem with the algebra