pls help me i don't know what to anwser

Answer:
1. 21 = 1,3,7,21
35 = 1,5,7,35
GCF = 7
2. 25 = 1,5,25
40 = 1,2,4,5,8,10,20,40
GCF = 5
3. 30 = 1,2,3,5,10,15,30
45 = 1,3,5,9,15,45
GCF = 15
Step-by-step explanation:
Hopefully it helps :)