Answer:
4. See attached
5. D. C(8) = 22
Explanation:
4. You want the graph of g(x) = -1/3x +5.
5. You want the functional form of the expression telling you the cost of 8 gallons of gas is $22, where C(x) represents the cost of x gallons.
4. Graph
The +5 in the equation g(x) = -1/3x +5 is the y-intercept. It tells you the point y=5 on the y-axis is on the line you want to graph.
The -1/3 in the equation is the slope of the line. This ratio tells you the line drops 1 unit for each 3 units to the right. That is, points (3, 4), (6, 3), (9, 2) will be on the line.
The graph is shown in the attachment.
5. C(x)
The problem statement tells you C(x) is the cost of x gallons. That is, ...
C(gallons) = dollars
Substituting the given values for gallons (8) and dollars (22), you have ...
C(8) = 22