00:01
All right, we need to solve this and we are going to use the quadratic formula, the negative b plus or minus b squared.
00:06
I'm not going to read it all.
00:07
But i'm going to highlight that our a value is a coefficient right here.
00:12
I thought i had my pen up.
00:13
The a value is 3.
00:15
The b value is negative 4 and the c value is negative 2.
00:19
Super important to know that because that's what i'm going to plug in here.
00:22
Excuse me.
00:24
So negative b and negative negative 4 is a positive 4 plus or minus.
00:30
Negative 4 squared is 16 minus 4 times our a value is 3 times our c value of negative all over 2a, which is 2 times 3.
00:47
Alright, i'm going to simplify across.
00:50
So why don't i do one thing here? maybe i'll do it in green.
00:55
16, well, let's do this.
00:56
4 times 3 is 12 and 12 times 2.
01:00
I'll keep the negatives.
01:01
Negative 4 times 3 is negative 12 and a negative 12 times a negative 2 is a positive 24.
01:09
So this whole thing's become 16 plus 24, which is 40 and so that's going to help us save room 4 plus or minus the square root of 40 over 2 times 3 is 6.
01:23
Alright, of course we're going to rewrite 40 to be 4 times 10 because that's going to be more useful for us because because because at this point we've probably seen in the lesson 4 is a square.
01:38
It is 2 squared so i can pull a 2 outside of that radical.
01:41
So now we got 4 plus or minus 2 square root 10.
01:47
And there's nothing else we can pull out a square root 10 because i mean that's 2 times 5.
01:51
No squares there...