I am sorry but I cannot see the picture properly, can you add another photo? Sorry for the inconvenience.
Given the slope m and a point (a,b) of a line, its equation is given by

In your case, a = -4, b = 7 and m=1/2, so we have

Since we are asked to find the rate of change from Monday to Wednesday, we are dividing by 2, since Monday is day 1 and Wednesday is day 3. 3 - 1 = 2.
1800 + 500 = 2300 calories consumed Tuesday.
2300 - 100 = 2200 calories Wednesday.
(2200 - 1800)/2 = 400/2 = 200 calories
Answer:
The price of the soda.
Step-by-step explanation:
The dependent variable is the variable defined to be dependent on another object, typically the independent variable. That means the variable that varies based off of another value is the dependent variable. In this situation, as the number of sodas bought increases, the total price increases. The price varies off of the number of sodas because the increase in sodas causes it to increase. Thus, the price is the dependent variable.
The range of a relation is the possible output values, the y-values.