00:01
Okay, then the intervals i want to find first are the changeover points where the sign will change, and that will be where each item becomes zero.
00:12
So 16 for this one, here minus 16, here is zero.
00:18
So each item is zero, and we get the number is minus 16, zero, and 16 in order.
00:27
So intervals then are going to be a number line to be clearer.
00:32
Here is minus 16, here is 0, here is plus 16.
00:39
This interval here on the left is going to be negative infinity up to minus 16.
00:49
And here it can be inclusive because if we put in minus 16, we'll get the 0.
00:57
That's okay.
00:59
Here then we're going to have minus 16 up to here it can't be zero because it can't divide by zero.
01:13
So here is zero.
01:16
Here is zero up to 16 and here we are 16 up to plus infinity.
01:28
Okay now at minus 16 i'm going to get zero as i will at plus 16 and we get zero.
01:39
Now let's find a sign of each section.
01:45
Take a number below minus 16 takes a minus 20 for example...