Three arithmetic means between 3 and negative 13

- 9, - 5, - 1

Step-by-step explanation:

Calculate the mean of 3 and - 13, that is

= = - 5

That is

- 13, - 5, 3

Now find the mean of - 13 and - 5, and - 5 and 3

= = - 9

= = - 1

Thus

- 13, - 9, - 5, - 1, 3

(f - g)(x) = 5x^3 - 3

step-by-step explanation:

rearrange these functions vertically, with like terms in separate columns:

f(x) = 5x^3 - 2

g(x) =         +1

now subtract, column by column:

(f - g)(x) = 5x^3 - 3