Which of these numbers are prime?

a
1
b
9
c
13
d
33

c 13

a prime number is a number that can only be divided by itself and 1

13 is prime

Step-by-step explanation:

It has only 2 factors: 1 and itself.

I hope it helps! :)

vbbv

step-by-step explanation:

answer: -10

step-by-step explanation:

s(t) = 1 - 10t

s(x) = 1 - 10x

s(x + h) = 1 - 10(x + h)

            = 1 - 10x - 10h

s(x + h) - s(x) = 1 - 10x - 10h - (1 - 10x)

                      = 1 - 10x - 10h - 1 + 10x

                      = -10h

= -10