CPM Homework Help : CCA Problem 7-15

For parts (a) and (b), find a recursive equation in a_n form for each sequence. (For a reminder about a_n form see the Math Notes box in Lesson 5.3.2.) For parts (c) and (d) find an explicit equation for each sequence. Homework Help ✎

$108,120,132,\dots$
Answer (a):
a₁ = 108a
a_n₊₁ = a_n+12

$\frac { 2 } { 5 }$ , $\frac { 4 } { 5 }$ , $\frac { 8 } { 5 }$ , …
Answer (b):
$a_1=\frac{2}{5}$
a₍_n_{+ 1)} = 2a_n

$3741,3702,3663,\dots$
Hint (c):
Is the sequence arithmetic or geometric?

$117,23.4,4.68,\dots$
Hint (d):
Is the sequence arithmetic or geometric?