00:02
So we have this quadratic and we'd like to convert it to standard form, also known as vertex form.
00:08
So we're going to factor this two out so that the x squared term has positive one as its coefficient.
00:15
And we're going to leave a big space for the magic completing the squared term.
00:20
Then we'll set aside the constant.
00:23
And since we're going to be adding a term, we also have to subtract it.
00:27
So we have to remember that two that we factor out and then whatever the magic term is.
00:32
And that magic term is b, which in this case here, once we factored out the two, is 10.
00:40
So b over two, and then we square it.
00:44
So that's going to be five squared.
00:47
So here we're going to have five squared.
00:50
And here we're going to have five squared.
00:53
Now we've got what we want.
00:54
We have our perfect square binomial.
00:58
So we get an x.
00:59
This negative sign says this sign's negative.
01:02
And the five is what we add here.
01:06
So we have that.
01:08
I got a little bit covered up.
01:10
Let's try that again.
01:16
The five is what goes in here.
01:19
So this binomial squared.
01:21
And what do we have here? two times five squared.
01:25
Well, five squared is 25.
01:26
Two times that is 50.
01:29
57 minus 50 is positive seven.
01:32
So this is plus seven.
01:36
So that's task a.
01:38
This is now in standard form.
01:40
Now we can find the vertex easily.
01:43
The vertex will jump right out at us.
01:45
It's going to be whatever this is times minus one.
01:49
So positive five.
01:51
And exactly whatever this is is the y coordinate.
01:54
So five comma seven is our vertex.
01:58
So we can go ahead and drop that on our graph.
02:00
Let's see.
02:02
Each of these horizontal lines is a roughly a quarter.
02:06
So seven is just shy of the three -quarters mark.
02:09
How about right about there? it'll probably be close enough.
02:15
Okay.
02:15
We also need to find x and y intercepts.
02:19
Well, this two is a positive.
02:22
That means our parabola's concave up.
02:25
Our vertex is above the x axis, so there are no x intercepts, right? the parabola is never going to cross.
02:36
No.
02:36
No x.
02:39
Oh, my goodness.
02:41
Let's try that again.
02:43
There will be no x intercept.
02:48
And you could show that by actually setting the function equal to zero and solving...