Answer: 1.25
Step-by-step explanation:
The explicit formula for the sequence is 
Substituting in n=4,

A=pi r^2
= 20.25 pi is the answer
What you do is you distribute the 5.
So your answer would be 5x+15
5x2(3x-1)+2(3x-1)factoring furhter gives(5x2+2)(3x-1)