Please help! I can't seem to figure this stuff out... Part 2

Phyllis and chen are saving money to go to a football game. each friend starts with some money and saves a specific amount each week. phyllis made a graph to show the total she has saved at the end of each week. chen wrote an equation to show the total, y, he has saved at the end of each week, x. y = 15x + 15 compare the amount that each friend has when both friends start saving. select the correct answer from the drop-down menu to complete the statement. phyllis starts with $ and chen starts with $

Given the equation f(x)=a(b)x where the initial value is 40 and the growth rate is 20% what is f(4)

Will mark brainlist what is the slope of the line passing through the points (-2, -8) and (-3,-9)? -7/5-5/71-1