Awildlife reserve had 8 elephant calves born during the summer and now has 31 total elephants. how many elephants were in the reserve before summer began. write an equation

Can you me find the missing length. i attached an image.

Ascientist has discovered an organism that produces five offspring exactly one hour after its own birth, and then goes on to live for one week without producing any additional offspring. each replicated organism also replicates at the same rate. at hour one, there is one organism. at hour two, there are five more organisms. how many total organisms are there at hour seven? 2,801 19,531 19,607 97.655

If 5x - 2 = -12, then x = a) -50 b) -4.4 c) -2.8 d) -2