How would you find all the possible numbers of rows, with out having if 8 is a factor of every number between 70 and 150

There can be many factors of a number.

So 1, 2, 3, 4, 6 and 12 are factors of 12.

And also -1,-2,-3,-4,-6 and -12, because you get a positive number when you multiply two negatives, such as (-2)×(-6) = 12

1, 2, 3, 4, 6, 12, -1, -2, -3, -4, -6, -12