1) Split the second term in
into two terms.

2) Factor out common terms in the first two terms, then in the last two terms.

3) Factor out the common term 

Answer:
The sequences which are geometric are
16,-8,4,-2,1
625,125,25,5,1
-15,-18,-21.6,-25.92,-31.104
Step-by-step explanation:
Geometric sequences are ones in which you multiply or divide to get the next terms in the sequence.
Cheers
Distribute the negative outside the parenthesis through the terms inside the parenthesis.
-c + 3 = 6
Subtract 3 from both sides.
-c = 3
Divide both sides by -1.
c = -3
11) 58 degrees for both angles
12) 72 and 108 degrees (left to right)
14) b=-3/2
I don’t have the rest I’m sorry