13. This works as the original number of coconuts must be able to be subtracted from 6/7 when one is subtracted from the original number and form an integer
37. In the last problem X: Is going to be -6(match the 6^7X on the left side to the -6^8 on the right. You need a negative and one more six to make the two terms equal)
38. In the last problem;I is going to equal -1(again match the -7^8i on the left to the 7^8 on the right)