Can someone my calculator broke and i can't finish it

An appliance salesman sets a goal to sell an average of 6 appliances per day for the first two weeks of his new job. the dot plot shows the number he sold each day during the first 13 days. what is the minimum number of appliances he must sell on the 14th day in order to reach his goal? a) 5 b) 6 c) 7 d) 8

100 points, hi, i’m not sure how to get the equation from the graph and table.

Write an expression that has three terms and simplifies to 4x - 7. identify the coefficient(s) and constant(s) in your expression