00:01
Given the function, t of x equals x cubed minus 3x squared plus 4x minus 12, we want to find the bounds of the real zeros.
00:16
We want to find the least upper and the greatest lower.
00:21
So let's start with the upper.
00:24
What we're looking for is a quotient row that is all positive.
00:29
So let's start with one.
00:33
If we synthetically divide 1 from our coefficients 1, negative 3, 4, negative 12, drop down the 1, multiply, add.
00:44
So we already got a negative.
00:45
It's not 1.
00:46
We need all positives.
00:47
So let's go to 2.
00:52
Drop down the 1, multiply, add, it's not 2.
00:57
Let's go to 3...