Answer:
17 & 19
Step-by-step explanation:
you can multipy 3x5 to get 15 so thats not it
you can multiply 8x2 to get 16 so its not prime
you can multiply 9x2 and 6x3 so thats not it either
1 is the only thing that can go into 17 besides itself and 1 is the only thing that can go into 19 besides itself
