Meaning if he did 10 chores he get's 70$ added so he did 10 now he has 285$ If he does 2 more chores that is 14$ more added.
So he now has 299$ so he done 12 chores and he needs 1 more dollar so if he did 1 more he gets 306$ and that was the least amount of chores he could do if he wanted 300$
the exponent x+2 means that the graph moves to the left 2 units and the value of K, which is -4, means that the graph will then move down 4 units from the parent function f(x)