00:01
This is basically a substitution problem where they're asking you to take this function for a square in minus 29a and see when that function is equal to negative 30.
00:19
And we might have two answers.
00:20
We might have no answers.
00:22
But basically the substitution is replacing f of a with negative 30.
00:28
I just rewrite in black right there.
00:31
Because at this point you have a quadratic and to solve a quadratic you want to set one side equal to zero.
00:37
You can do that by adding 30 to the right side.
00:41
And i know some teachers don't like the slide and divide method, but it works so well that i feel like it's good for students to know this, that you get 120.
00:53
And then factors of 120 that would add to be 29.
00:58
Let's see, 120 divided by 20 just for a baseline is 6.
01:03
So that's not correct, but it's pretty close.
01:06
120 and divided by 15.
01:09
Let's see, 8 and 15.
01:13
I'm getting further away from 29.
01:16
So what if i did 120 divided by, let's see, five? there we go...