Tutor.com Quadratic Equations Session

May. 24, 2012

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Session Transcript - Math - Algebra, 5/15/2012 7:37PM - Tutor.comSession Date: 5/15/2012 7:37PM
Length: 24.1 minute(s)
Subject: Math - Algebra


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

Fran (Customer)
[00:00:04] Hi how are you

Gautham K (Tutor)
[00:00:04] Welcome to Tutor.com ! Let's get started.

Fran (Customer)
[00:00:37] may I write my question on the board

Gautham K (Tutor)
[00:00:39] Yes go ahead.

Fran (Customer)
[00:01:08] is it -1

Gautham K (Tutor)
[00:01:13] let me clarify first
[00:01:21] does that say 1 - 4/7 ?

Fran (Customer)
[00:01:35] y

Gautham K (Tutor)
[00:01:33] oh ok
[00:01:41] and you said y = -1 ?

Fran (Customer)
[00:01:53] yes

Gautham K (Tutor)
[00:01:53] that's correct!

Fran (Customer)
[00:02:15] may I try another one

Gautham K (Tutor)
[00:02:13] yes
[00:02:48] ok

Fran (Customer)
[00:03:03] I don't know how to do this one

Gautham K (Tutor)
[00:03:12] ok let me show the steps to do this

Fran (Customer)
[00:03:36] ok

Gautham K (Tutor)
[00:04:03] are you familiar with quadratic equations?

Fran (Customer)
[00:04:38] I was told to cross multiply

Gautham K (Tutor)
[00:04:41] yes that is the first step
[00:04:53] but once you do that, you will end up with a quadratic equation as a product

Fran (Customer)
[00:05:12] ok

Gautham K (Tutor)
[00:05:44] can you try multiplying x-3 by x+4 and show me what you get?

Fran (Customer)
[00:06:13] x^2

Gautham K (Tutor)
[00:06:15] that's part of it
[00:06:31] are you familiar with the FOIL method?

Fran (Customer)
[00:06:37] + x - 12

Gautham K (Tutor)
[00:06:39] ok that's right!

Fran (Customer)
[00:06:45] yes

Gautham K (Tutor)
[00:06:58] and what about the right side?

Fran (Customer)
[00:07:25] 132 - 6x

Gautham K (Tutor)
[00:07:24] right
[00:08:10] now can you try combining things so you end up with an equation that equals 0?
[00:08:21] first, how would you get rid of the 132
[00:08:29] from the right side I mean

Fran (Customer)
[00:09:06] - 132

Gautham K (Tutor)
[00:09:15] and the -6x?

Fran (Customer)
[00:09:33] + 6x

Gautham K (Tutor)
[00:09:31] right
[00:10:04] now this is a quadratic equation right?

Fran (Customer)
[00:10:14] Hess
[00:10:17] Hess
[00:10:20] yes

Gautham K (Tutor)
[00:10:46] ok, how would you solve this? do you want to try factoring or go straight to the quadratic formula to solve for values of x?

Fran (Customer)
[00:11:33] factoring trinomial

Gautham K (Tutor)
[00:11:32] ok
[00:11:37] so what are two numbers
[00:11:48] that when multiplied together gives -144

Fran (Customer)
[00:12:01] I'm figuring

Gautham K (Tutor)
[00:11:58] but added together gets 7?
[00:12:00] Ok

Fran (Customer)
[00:12:20] yes

Gautham K (Tutor)
[00:13:53] is there any problem you are having ?

Fran (Customer)
[00:14:12] I'm still finding factors

Gautham K (Tutor)
[00:14:12] ok

Fran (Customer)
[00:14:33] I'm unsure

Gautham K (Tutor)
[00:14:48] if you are unsure, do you want to try the quadratic formula?
[00:14:56] that way there is no guesswork to find the factors
[00:15:06] its all plugging in to the formula

Fran (Customer)
[00:15:18] no

Gautham K (Tutor)
[00:15:18] ok,
[00:15:23] what are the factors you tried?

Fran (Customer)
[00:16:01] 8 18

Gautham K (Tutor)
[00:16:06] that's a good try
[00:16:19] what about the next number after 8
[00:16:41] is there any number times 9 that = 144

Fran (Customer)
[00:16:50] 9 18

Gautham K (Tutor)
[00:16:55] 9 times 18 = 162

Fran (Customer)
[00:17:09] 16

Gautham K (Tutor)
[00:17:07] right
[00:17:16] which one is negative and which one is positive?

Fran (Customer)
[00:17:42] 16 positive

Gautham K (Tutor)
[00:17:41] yes

Fran (Customer)
[00:18:15] x - 9 x + 16

Gautham K (Tutor)
[00:18:35] oh one second
[00:18:40] theres a small mistake

Fran (Customer)
[00:19:10] ok

Gautham K (Tutor)
[00:19:10] you have to write it like i did
[00:19:13] in factor form
[00:19:18] do you see that?

Fran (Customer)
[00:19:45] no

Gautham K (Tutor)
[00:19:49] i have boxed it on the board

Fran (Customer)
[00:20:04] yes

Gautham K (Tutor)
[00:20:17] if you apply FOIL to this
[00:20:22] you will get the equation above
[00:20:25] is that clear?

Fran (Customer)
[00:20:38] yes

Gautham K (Tutor)
[00:20:38] ok now, you can find x
[00:20:44] what are the 2 values of x?

Fran (Customer)
[00:21:11] x

Gautham K (Tutor)
[00:21:25] remember, the equation should equal 0

Fran (Customer)
[00:22:04] yes

Gautham K (Tutor)
[00:22:02] so what value of x would make the quantity inside the parenthesis (x+16) equal to 0

Fran (Customer)
[00:22:19] ok

Gautham K (Tutor)
[00:22:28] what value of x would make it 0?
[00:22:33] x+16 = 0
[00:22:35] what is x?

Fran (Customer)
[00:22:54] -16

Gautham K (Tutor)
[00:22:53] correct!
[00:23:00] and similarly for x-9 = 0
[00:23:02] what is x?

Fran (Customer)
[00:23:17] 9

Gautham K (Tutor)
[00:23:20] there you go
[00:23:27] x = -16 and x = 9
[00:23:29] are the answers
[00:23:32] is that all clear now?

Fran (Customer)
[00:23:53] yes

Gautham K (Tutor)
[00:23:52] great!
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