What is the missing number pls help

Answer:
So in order to find the missing number, we must find the difference with the numbers that we were given.
Problem #1
42-30= 12 and 84-69= 15. It's possible that each difference increases by one Let's see...
30+12= 42
42+13= 55
55+14 = 69
69+15 = 84
So for 1., all you have to do is keep adding the difference and increase it by 1 each time. If you wanted to keep increasing, you would add 84+16, then 100+17, etc.
Problem #2: As for the second one, I had trouble solving it, sorry :(.
Problem #3
3. For the third problem, 27-22= 5 and 9-1=8. It looks like each difference increased by 1.
27-22 = 5
22-6 = 16
16-7 = 9
9-8= 1