The slope between the points (-1,-5) and (r, -9) is 2. What is the value of r?

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.

Num of plants = (original#ofplants)*(1.6)^t