00:01
Okay, so we're given the equation x squared plus 4x equals negative 3.
00:11
Now what we're going to do is solve this quadratic, and we're going to try to do it with only 3 % battery life left.
00:21
Let's see if we can do it in time.
00:22
So the first thing we want to do is we want to factor this, and to do that we need to complete the square.
00:30
So the best way to complete the square is if you just remember this easy, easy step and easy trick.
00:37
You want to take the b term, and by b term, i mean a, x squared plus bx plus c equals whatever.
00:47
And the b term is this right here, just the x.
00:51
So we want to take this b term, and the first thing we want to do is we want to half it.
00:58
And then we want to square it, and then we want to add it, and then subtract it.
01:09
So all you need to remember for completing the square is take the b term, and then half it, square, add it, subtracted.
01:17
So just keep that in your head, just half it, square, add it, subtract it.
01:20
Just keep saying that over and over again, so you remember it, half it, square, add it, subtract it.
01:24
So what we want to do is we want to take the b term, which is four, we want to half it, which equals 2.
01:33
And then we want to square it, which equals 4 again.
01:37
And then we add it, so we take the original equation, and then we add it plus 4, and then we subtract it minus 4 equals minus 3...