Answer:
Step-by-step explanation:
Each term of this Geometric Series (3, −6, 12, −24, ...) can also be found through this explicit formula: Because the 
term is found by the product of its common ratio "q", times its predecessor n-1. Where n, refers to the order of the term.
So let's test it, suppose we want to find the 4th term. We know the common ratio and the first term. Then we can write f(n) as:
f(4)=f(3)*-2⇒-24=12*-2⇒-24=-24
The explicit formula is ok.
I’m thinking your r in the first equation is actually an x.
X + 2(2x -4) =10
X +4x -8 =10
5x = 18
To solve the given equation, you would need to multiply t by both terms inside the parenthesis.
The equation would be D. (t*14) - (t*5)
If 10% of songs represents 6 songs,
then 100% of songs represents (100 * 6) / 10 = 60 songs
The playlist has a total of 60 songs.
