Please answer i will mark brainliest!!

16 and 3

Step-by-step explanation:

A prime number has only 2 factors, 1 and itself

2, 5 and 7 meet this criteria and are prime, however

factors of 16 are 1, 2, 4, 8, 16

16 does not meet the criteria and is not prime

The factors of 18 are 1, 2, 3, 6, 9, 18

The only one of these factors which is prime is 3

a28=58

step-by-step explanation:

a1=a1+(n-1)d

a28= 4+ (28-1)2

a28=4+(27)(2)

a28=4+54

a28=58