00:01
Okay, this is the problem just as it's given in the book.
00:05
And we're trying to find the number k so that this is true.
00:17
And so my kind of strategy here that i would employ is just like foiling on the left -hand side.
00:26
So that's where i'm going to start.
00:28
So the foil, we do first times first.
00:31
That would be 12x squared.
00:34
And then the outer, so 3x times 3k, that would be plus 9x.
00:44
Okay.
00:45
And then inner, negative 2k times 4x would be negative 8x.
00:54
And then last for the l for foil.
00:59
So negative 2k plus 3 .2.
01:01
That would be a negative 6k squared.
01:06
So i'm going to combine like terms here.
01:09
This is going to give me 12x squared plus xk minus 6k squared...