Tutor.com Quadratic Functions Session

Apr. 27, 2013

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Session Transcript - College Algebra - College Algebra, 4/16/2013 2:52PM - Tutor.comSession Date: 4/16/2013 2:52PM
Length: 24.6 minute(s)
Subject: College Algebra - College Algebra


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

Guest (Customer)
[00:00:00] 5x^2-5x-xy+y

System Message
[00:00:00] *** The student has 144 minutes remaining. ***

Katy W (Tutor)
[00:00:11] Hi welcome to Tutor.com !

Guest (Customer)
[00:00:15] Hi Katy, thank you in advance for helping me today.

Katy W (Tutor)
[00:00:29] you are welcome in advance what are we doing with this expression today?

Guest (Customer)
[00:00:53] Factoring it out

Katy W (Tutor)
[00:01:03] ahhh ok
[00:01:08] have you worked on it some already?

Guest (Customer)
[00:01:28] I've tried, but I don't understand this stuff at all.

Katy W (Tutor)
[00:01:44] ok

Guest (Customer)
[00:01:52] I know with 4 terms you are suppose to factor by grouping

Katy W (Tutor)
[00:02:02] a lot of times when you are given 4 terms to factor, a good first way to try is factor by grouping - have you heard of this before?
[00:02:07] ah, we were typing the same stuff

Guest (Customer)
[00:02:25] That means I am on the right track, ha ha.

Katy W (Tutor)
[00:02:50] ok
[00:03:04] when I am factoring by grouping, I actually like to rewrite the problem with the groupings I'm going to try
[00:03:07] it helps me focus
[00:03:20] are you ok with how I rewrote that?

Guest (Customer)
[00:03:29] Yes, that is how we are suppose to do as well

Katy W (Tutor)
[00:03:34] ok
[00:03:38] so let's look at the blue (left) group
[00:03:48] what is in common between 5x^2 and 5x?

Guest (Customer)
[00:03:56] 5x?

Katy W (Tutor)
[00:03:59] yes!
[00:04:14] what is 'left over' in the grouping if I pull 5x from both terms?

Guest (Customer)
[00:04:46] x

Katy W (Tutor)
[00:04:56] how about from the -5x?

Guest (Customer)
[00:05:19] Umm...1?

Katy W (Tutor)
[00:05:29] close! we're going to keep the sign... so -1
[00:05:30] make sense?

Guest (Customer)
[00:05:45] Yes

Katy W (Tutor)
[00:05:48] you'll notice if I used distributive property on my blue group, I'd end up where I started - which is what we want
[00:05:51] that is a good way to check your signs

Guest (Customer)
[00:06:03] Got it

Katy W (Tutor)
[00:06:10] ok how about the second grouping in green?

Guest (Customer)
[00:06:22] hmm, factor out the...y?

Katy W (Tutor)
[00:06:26] yeah!
[00:06:32] what's left?

Guest (Customer)
[00:06:47] x=1
[00:06:54] x-q

Katy W (Tutor)
[00:06:58] hehehe

Guest (Customer)
[00:07:00] grr, I can not type today!
[00:07:03] x-1

Katy W (Tutor)
[00:07:29] remember - we want to keep the signs right now... if we distributed y(-x+1) we'd have -xy+y, so we're in good shape this way
[00:07:40] so

Guest (Customer)
[00:07:41] Oh, okay
[00:07:45] the signs confuse me.

Katy W (Tutor)
[00:07:49] what we hope for when we factor by grouping is that the group leftovers match
[00:07:58] these don't seem to match, do they?

Guest (Customer)
[00:08:04] definitely not

Katy W (Tutor)
[00:08:07] ok
[00:08:12] I am going to show you a useful algebra twist
[00:08:31] if we had pulled out a -y instead of +y
[00:08:45] the green group could look like this
[00:08:51] if I distribute, it still makes -xy + y

Guest (Customer)
[00:09:00] oh!

Katy W (Tutor)
[00:09:03] do you see the difference?
[00:10:11] what do you think?

Guest (Customer)
[00:10:29] Yes
[00:10:37] lets see

Katy W (Tutor)
[00:10:39] canyou finish from here?

Guest (Customer)
[00:10:52] the next step is (x-1)(5x-y)?

Katy W (Tutor)
[00:10:58] you got it!
[00:11:05] and you can FOIL that if you wanted to check, and compare it to the original
[00:11:09] that is one reason I like factoring problems
[00:11:14] you can allllways check them

Guest (Customer)
[00:11:40] I don't know why this seems so hard to me

Katy W (Tutor)
[00:11:47] are you fairly new to it?

Guest (Customer)
[00:11:53] The last 2 steps I am fine with. It's the starting point I have problems with.
[00:12:03] Yes, I am a 30yr old college freshman, lol.

Katy W (Tutor)
[00:12:07] ahhh
[00:12:14] then that is a very normal feeling to have!
[00:12:19] factoring gets 'easier' the more you do it
[00:12:28] sort of like when you learned to multiply and divide back in elem school

Guest (Customer)
[00:12:27] any chance we could do one more

Katy W (Tutor)
[00:12:33] sure let's try one more
[00:13:54] ok
[00:13:58] what did we do first last time?

Guest (Customer)
[00:14:11] We grouped, since it has 4 terms

Katy W (Tutor)
[00:14:18] yep
[00:14:25] do you want to write the two groupings, or do you want me to do it?

Guest (Customer)
[00:14:39] I can

Katy W (Tutor)
[00:14:51] awesome

Guest (Customer)
[00:15:27] err, I am not sure how to change the colors on whiteboard

Katy W (Tutor)
[00:15:41] don't worry about it
[00:17:10] loooookin good

Guest (Customer)
[00:17:43] ?

Katy W (Tutor)
[00:17:51] really close!
[00:18:01] is there anything left in the second grouping that could be factored out? loook closely

Guest (Customer)
[00:18:26] oh! the 4?

Katy W (Tutor)
[00:18:29] yeah!
[00:18:34] let's pull that out and see what happens
[00:20:22] You got it!
[00:20:29] you did awesome with this one!
[00:20:34] even though it had all those variables going on
[00:20:36] I am impressed

Guest (Customer)
[00:20:55] Thanks.
[00:21:11] I think the grouping ones I can do pretty well. It's the others I have problems with.
[00:21:18] The ones about perfect squares and such

Katy W (Tutor)
[00:21:29] yeah those are just a matter of identifying the pattern and applying the formula
[00:21:36] they get easier with practice
[00:21:47] do you know the website khanacademy.org ?

Guest (Customer)
[00:21:59] I've heard of it, but I have never gone to the site.

Katy W (Tutor)
[00:22:09] ok
[00:22:14] it might be a great resource for you
[00:22:18] most people know it for the math videos
[00:22:23] but they have a new part where you can do practice problems
[00:22:39] it would be a good way to get your hands on more factoring problems to try, and it will give you hints and link to relevant videos

Guest (Customer)
[00:22:44] Is it sort of like MyMathLab?

Katy W (Tutor)
[00:22:53] in a way, I like it a bit better since its free
[00:23:00] and because it really has a good video library to go with it

Guest (Customer)
[00:23:01] Haha, free is good.
[00:23:17] I'll definitely check it out. I need all the help I can get.

Katy W (Tutor)
[00:23:21] you can also track your progress and earn points and badges and stuff, if that is motivating
[00:23:43] you can do it - just stick with it, ok?

Guest (Customer)
[00:24:16] Definitely
[00:24:20] thank you so much

Katy W (Tutor)
[00:24:25] you are welcome!
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