Is (0,2) (0,4) (1,6) (3,10) a function?

No

Step-by-step explanation:

since the X repeats with a 0

(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