00:01
So here we know that john's old 87 labaron gets, it has a 15 -gallon gas tank, and it gets 23 miles per gallon.
00:12
So i'll write that down, 23 miles per gallon, and it's a 15 -gallon tank.
00:23
And we're told that the number of miles that he can drive, i'll denote that quantity by d.
00:29
So the number of miles that he can drive is a function of how much gas is in the tank.
00:36
So let's let d equal number of miles.
00:45
We can drive.
00:48
We'll just let x equal the amount of gas in the tank, right, measured in gallons.
01:00
And we want to, in part a, write this relationship, an equation form.
01:05
So we know that d, so it depends on x.
01:10
I'll write it in actual function notation.
01:12
So d is equal to, well, you can take the number of gallons of gas he has and multiply by the miles per gallon.
01:24
You can go.
01:26
So for example, if you only had one gallon of gas left, you could go 23 miles on that one gallon.
01:33
Whereas if you had five gallons left, you could do that five different times, right? so it would be five times 23.
01:40
So this is our relationship.
01:43
And it's a linear function.
01:46
I plot the graph real quick.
01:48
It's just a straight line that passes to the origin with the slope of 23.
01:52
It looks something like this...