00:02
In this equation, we are going to use the standard form of a circle, the equation of a standard form of a circle.
00:08
This is our formula where the center is in the form hk, and the radius is here.
00:16
It gives us radius squared, so we'll have to solve for just radius.
00:22
So our equation is x squared plus y squared plus 2x plus 10y plus 17.
00:39
Let's make that so we can read it.
00:44
Plus 17 equals 0.
00:55
Okay, so we are going to first use a technique called completing the square.
01:04
In order to do that, we're going to rearrange our equation so that our x terms are first.
01:12
So i have this x squared and this plus 2x.
01:17
That's a 2.
01:19
We're going to leave some room to complete the square on that one.
01:23
Then we're going to get our y terms.
01:29
We're going to leave some room here.
01:31
And then we're going to move the 17 to the other side by subtracting 17.
01:37
So this is going to equal negative 17.
01:44
Now we want to complete the square on x squared plus 2x.
01:49
So we want to add something here that would make this part a perfect square.
01:53
Trinomial.
01:54
In order to do that, we're going to take half of this two, which is one, and write it here.
02:00
We're going to square the one and add it here.
02:04
And if we add it to one side, we have to add it to the other side as well.
02:10
So we've added it here and here to keep our equation balanced.
02:17
Okay.
02:18
Now for the y part, we're going to take half of the 10, which is five.
02:22
We're going to write that right there...
