00:01
So we have this function f of x.
00:03
We're going to find the value of f of x plus h.
00:07
So i'm just going to plug in x plus h in for each value or each variable x in our function f of x.
00:16
So that's going to be x plus h times in parentheses x plus h plus 40, which is just x plus h times x plus h plus 40.
00:28
And now i'm going to do this multiplication, so we're going to get x squared plus x -h plus 40x, and then we're going to have plus h times x or x times h, and then plus h squared and plus 40 -h.
00:49
So we can combine these two x -h terms, and so this is going to simplify to x -square to x -squared plus 2xh plus 40x plus h squared plus 40 h.
01:09
The next thing we're gonna do is we're gonna take what we found in part a, so x squared plus 2xh plus 40x plus h squared plus 40h.
01:23
And we're going to minus f of x from it.
01:26
So we're going to minus our original equation.
01:28
And i'm going to distribute this x before i do this, it's going to make things easier for us.
01:34
So this is equal to x squared plus 40x...