00:01
All right, we need to find the slope of this line right here.
00:08
And remember, slope is the change in the rising part, which is y.
00:15
The change in y over change in x, which is the running part.
00:23
So let's notice that the change in y is talking about, from here, here up that change right here so it's going from f of a to f of a plus h so we have to use this function that they provided us f of x and plug in a and a plus h and then we will take the differences of them to find that difference here okay so f of a let's start with that one you just strictly substitute a in for x.
01:06
So just another variable.
01:08
And now i have that.
01:12
F of a plus h, kind of the same thing.
01:16
But now instead of x, we've got to plug in the whole thing, a plus h squared plus 5.
01:25
Okay, so now i'm going to factor out that a plus h squared.
01:32
Okay, and remember that's a plus h times a plus h.
01:39
Here we go.
01:42
So, um, foil, right? first is a times a, a squared.
01:48
Outer is a times h.
01:54
Inner a times h again.
01:58
I'm going to keep it in that order.
02:01
And last, h times h, h squared.
02:05
Okay, i'm just going to put the ahs together and there are just two of them.
02:17
Okay, so now when i take my equation that i just had, this long one, right, this upper point up here, and i subtract my lower point here that we found earlier, well look at this, the a squared, subtracts with this a square...