So I understand how to solve it the questions but I think my knowledge of exponents is causing me problems:

Determine if the sequence {a(n)} is a solution of the recurrence relation a(n) = -3*a(n-1) + 4*a(n-2) if a(n) = 2*(-4)^n+3

I started as below substituting in the formula:

a(n) = -3( 2(-4)^(n-1)+3) + 4( 2(-4)^(n-2) + 3)

= ( -3 *2* -4^(n-1) -9) + 2 * -4^(n-1) + 12

However,

I am having trouble with the first term. Any help would be appreciated.