4x is the slope (another word for the rate of change) of the equation above. (it's quite obvious if you know the formula and what the variable mean.) This is Slope-intercept form- y = mx + b. M is the slope and b is the y-intercept. Now for the graph. This is quite simple to find the slope. The slope is also known as rise over run, meaning how many times it rises over how many times it goes to the side. Let's pick a point on the graph to count. Start at (0,2). Count the squares to the points where the line touches a corner of it. (sorry I'm not good at explaining. I hope you get what I mean.) So from the point (0,2) and count to the side and upwards. The rise (how many squares you went up) is 2, and the run (how many squares you went across) is 1.
(rise over run) rise is 2, and run is 1 so it's 1/2. Or just 2 because 2 ÷ 1 is still 2. Hope it wasn't to complicating. Good luck!
The car goes 23.2 miles every gallon, so with 15 gallons (15 * 23.2 = 348) it can go 348 miles. With the extra .25 that the car has, it can go 0.25 * 23.2 = 5.8 miles. 348 miles plus the 5.8 miles gets you 353.8 miles on 15.25 gallons.
