Answer:
18
Step-by-step explanation:
bc 8 digits in the ones place, and less than 21 greater than 15
Errrmmm.... Where is the expression?
20x26=520
The answer is D 520.
Hope it helps.


distributed
choose 1 as your lowest positive integer
plug 1 into a and b
1 + 1 + 1 + 1