Sequences -

Linear -

An → FirstTerm + Difference(n -1)

Quadratic -

1. a + b + c
2. 3a + b
3. 2a

Cubic -

1. a + b + c + d
2. 7a + 3b + c
3. 12a + 2b
4. 6a

Geometric -

n = FirstTerm(Second/First)^n-1

Alternating Between Positive & Negative =

KEEP A NEGATIVE NUMBER IN THE BRACKETS IN GEOMETRIC

eg

2(-2)^n-1