00:01
When you're first learning two factor, looking at x squared minus 9x, and this last number is plus 8, the whole thought process, even though they give you one of the factors, is that you're undoing the distributive property.
00:17
And when you're doing the distributive property, we want the two numbers to add to be negative 9, so their sum is negative 9, but then they also multiply to be 8.
00:26
So that would be a product of 8.
00:28
And what i like to do is just write out all the factors of eight.
00:33
And that's it.
00:34
Now, the only way they get it so it's a negative nine is if both numbers are negative.
00:41
Because they still multiply negative times a negative is still positive eight.
00:45
But negative one plus negative eight gives me the negative nine that i want...