00:01
Okay, the first step here is the factor of the denominator.
00:04
So i get 5a plus 10.
00:08
A squared minus b squared.
00:10
It's a minus b times a plus b.
00:13
There is a squared minus 2 squared.
00:16
So a minus 2 times a plus 2.
00:21
That's part a.
00:23
Now undefined, i can't divide by 0.
00:27
So i know that a cannot be 2 or.
00:31
Or minus 2.
00:35
Now if i carry on with this one, the top has a factor of 5, a plus 2.
00:44
The bottom we just did, a minus 2 times a plus 2, and then that and that counts out and we're left with 5 over a minus 2.
01:03
Now next part, a equals minus 2.
01:14
5 over a minus 2 will become 5 over negative 4.
01:22
If a is plus 2, then 5 over a minus 2 is 5 over 0, which is undefined.
01:37
So it's different because i've cancelled out here, the a plus 2, top and bottom...