M = -9 ; solve for m by simplifying both sides of the equation, then isolating the varible
Answer:

Step-by-step explanation:
Let p represent cost of each drink.
We have been given that the medium pizza costs two times as much as one drink, so the cost of medium pizza would be
.
We are also told that the large pizza costs three times as much as one drink, so the cost of la pizza would be
.
We have been given that Mary wants to buy one large pizza, one medium pizza, and three drinks.
Since the cost of one drink is p, so cost of 3 three drinks would be
.
The total cost of one large pizza, one medium pizza, and three drinks would be 
Mary started with $30, so amount left after all of her purchases would be 30 minus total cost of all purchases.

Therefore, Mary will have
dollars left after making all of her purchases.
1. Slope = rate of change
Shown on the graph, for 2016 there are 36 entries. For 2017, there are 40
Since it’s only one year
You can subtract 36 from 40
40 - 36 = 4
Solution: the slope is 4
2. Months increase the most, the lines which are steeper and going upward (since it’s increasing)
Solution: from 2015 to 2016
Ok so linear equations come in the form
y = mx + b
B is the y-intercept. In this equation the y intercept is 40. A y- intercept is where the graph crosses the y axis so at the point (0,40) the graph crosses the y axis.
M is the slope which is rise over run so if the slope was 10 (which it is) 10 is equivalent to 10/1 so you move up 10 units for every 1 unit you move across.
So to graph this equation, you would draw your first point at (0,40). For your next point, you would move right one unit, and up 10 units. Draw a point there which would be (1, 50). Hopefully you understand. For going left from the y intercept point, you would move left 1 and down 10.
Actual graph above.
Hope this helps C: