# Tutor.com Functions Session

##### Oct. 28, 2013

Session Transcript - Math - Calculus, 10/26/2013 6:07PM - Tutor.comSession Date: 10/26/2013 6:07PM
Length: 13.4 minute(s)
Subject: Math - Calculus

System Message
[00:00:00] *** Please note: All sessions are recorded for quality control. ***

Johnson (Customer)
[00:00:00] Find the focus of y^2+6y+8x+25=0

Michael H (Tutor)
[00:00:10] Good afternoon.

Johnson (Customer)
[00:00:15] Hello!

Michael H (Tutor)
[00:00:42] So I see you need to find the focus of a quadratic.

Johnson (Customer)
[00:00:44] yes

Michael H (Tutor)
[00:00:47] Any ideas how to begin?

Johnson (Customer)
[00:00:50] hmm
[00:00:50] well
[00:01:47] so this is where I got stuck :/ i wasnt sure what to do from here

Michael H (Tutor)
[00:01:51] Where did the +9 come from?

Johnson (Customer)
[00:02:01] 6/2 = 3
[00:02:04] 3^2 = 9

Michael H (Tutor)
[00:02:30] 9 is the value you want for completing the square.
[00:02:49] But remember that if you want to add it to one side of the equation you have to add it to the other side as well.

Johnson (Customer)
[00:02:58] i did,
[00:03:01] -25 = 9
[00:03:05] -25 + 9

Michael H (Tutor)
[00:03:09] Ah, I see what you did.

Johnson (Customer)
[00:03:16] YES
[00:03:19] yes

Michael H (Tutor)
[00:04:39] So this is starting to look a little bit like the general form of the equation of a parabola.

Johnson (Customer)
[00:04:44] yeah

Michael H (Tutor)
[00:05:18] Could we rearrange things a bit so they look like that?

Johnson (Customer)
[00:05:31] hmm
[00:05:32] umm
[00:06:23] like that?

Michael H (Tutor)
[00:06:53] Ok. And any way we could get the x by itself?

Johnson (Customer)
[00:07:26] like that?

Michael H (Tutor)
[00:07:41] Good. Or rewritten slightly.

Johnson (Customer)
[00:08:15] the center is (-2,-3)?
[00:08:29] And p is -2?
[00:08:55] so focus is (-4,-3)

Michael H (Tutor)
[00:09:15] I'm working on this...
[00:11:43] Why is p -2?

Johnson (Customer)