Review question

# If $u_n = a + bn + c2^n$, what's the sum of the first $n$ terms? Add to your resource collection Remove from your resource collection Add notes to this resource View your notes for this resource

Ref: R6153

## Question

The $n$th term of a certain series is of the form $a+bn+c2^n$, where $a$, $b$, and $c$ are numbers. If the first three terms are $2$, $-1$, and $3$, find the values of $a$, $b$, and $c$, and the sum of the first $n$ terms.