So, for these questions you get a sequence:
U_{n}=4U_{n-1}-5U_{n-2}+2U_{n-3}
and you're given something else:
U_{n}=2^{n-1}-3n+5
& a set of 'conditions':
U_{1}=3,U_{2}=1,U_{3}=0
But what do you actually have to PROVE, and what steps do you take to do it?
Can somebody prove it...