The value of a term is 2 more than 7 times its term number! What is the answer? Please explain

Suppose there is a simple index of three stocks, stock abc, stock xyz, and stock qrs. stock abc opens on day 1 with 4000 shares at $3.15 per share. stock xyz opens on day 1 with 5000 shares at $4.30 per share. stock qrs opens on day 1 with 6000 shares at $4.60 per share. the price of stock abc on day 8 begins at $3.50. the price of stock xyz on day 8 begins at $3.90. stock qrs opens on day 8 with a price of $4.50 per share. assume that each stock has the same number of shares that it opened with on day 1. what is the rate of change of this simple index over 1 week?

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

What is the radius of a circle with an area of 78.5 cubic inches? use 3.14 for pie