Option 1! If you expand the bracket and simplify.
The estimate should be 6.92
Very interesting question!
Let's try to get something that would work for just 5 for now.
Any of these numbers would leave a remainder of 1 when divided by just 5:
6, 11, 16, 21, 26, 31, 36, 41, 46, 51, 56, 61, 66, 71, 76, 81, 86, ...
Notice that they all look like 5*(something) + 1. Basically, they are all multiples of 5 plus 1.
Let's see what would work for just 8:
9, 17, 25, 33, 41, 49, 57, 65, 73, 81, 89, ...
Are there any matches... AHA! It's 81. This is the lowest positive integer greater than 1 that follows the rule for both 5 and 8.
That is not always true because think of it as ab=8 that is just like saying (8)(8)=8 which is absolutely false. If anything it can be either a or be equals 8 while the other variable is 1. (1)(8)=8 or (8)(1)=8
