What is a circumference?

(if f(x)=4x^2 and g(x)=x+1, find (f o g)(x)

Customers at an ice-cream shop took a survey .the results showed that 144 customers rated the shop as being "very satisfactory ."this number represented 45%of the total nunber of customers who took the survey

For f(x)=2x+3 and g(x)=x^2- 8 find (f+g) (x)