00:01
All right, we got x cubed plus 5x squared plus 4 x is less than 0.
00:04
Let's start factoring.
00:05
So that's x into x squared plus 5x plus 4 is less than 0.
00:11
So let's factor this even further.
00:13
So x plus 4 into x plus 1.
00:18
Now we can work on this.
00:20
So our critical points, 0, minus 4, and minus 1.
00:26
So those are the values that give us 0.
00:28
So our number line here can have minus 4.
00:32
I usually use the number line for visuals, minus 1 and 0.
00:36
So a, b, c, d.
00:39
We're going to have four regions now...