# Tutor.com Polynomials Session

##### Mar. 8, 2012

Session Transcript - Math - Algebra II, 3/1/2012 12:24AM - Tutor.comSession Date: 3/1/2012 12:24AM
Length: 18 minute(s)
Subject: Math - Algebra II

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

Phil (Customer)
[00:00:00] 2x^2 + 8x - 15 = 0

Timothy M (Tutor)
[00:00:14] Welcome to Tutor.com ! Let's get started.

Phil (Customer)
[00:00:18] okay

Timothy M (Tutor)
[00:00:24] What are the instructions for this problem?

Phil (Customer)
[00:00:52] completing the square

Timothy M (Tutor)
[00:01:21] Okay, so we want to solve for x by completing the square?

Phil (Customer)
[00:01:25] yes

Timothy M (Tutor)
[00:01:58] Excellent, and would you like it demonstrated in detail?

Phil (Customer)

Timothy M (Tutor)
[00:02:08] Okay.
[00:02:30] So the first thing we will do to complete the square is to get rid of the two in the first term.
[00:02:40] To do this we will divide all terms by 2.
[00:02:47] Which will give us, this...

Phil (Customer)
[00:02:47] ok

Timothy M (Tutor)
[00:03:18] Any questions about that step?
[00:05:12] Let's move the 7.5 to the other side of the equals sign.

Phil (Customer)
[00:05:14] ok

Timothy M (Tutor)
[00:05:17] How would we do that?

Phil (Customer)

Timothy M (Tutor)
[00:05:38] Right on, and what will that give us?
[00:07:24] That is correct.
[00:07:54] Next we will take the 4 from the second term, divide it in half, then square it and add it to both signs of the equal sign.
[00:08:00] What will that give us?
[00:09:30] Great work on the left side.
[00:09:44] Then what we do to one side we must do to the other.

Phil (Customer)

Timothy M (Tutor)
[00:10:11] Oh okay, thanks.
[00:10:23] So lets rewrite it below that equation.

Phil (Customer)
[00:10:45] okay

Timothy M (Tutor)
[00:10:54] Next we want to factor the left side of the equation.
[00:11:08] How does x^2+4x+4 factor?

Phil (Customer)
[00:11:15] (x+2)^2
[00:11:17] pretty simple

Timothy M (Tutor)
[00:11:25] Right on.
[00:12:03] Next how would we get rid of the squared on the left hand side of the equals sign?

Phil (Customer)
[00:12:40] square rot
[00:12:42] *root
[00:12:44] both sides

Timothy M (Tutor)
[00:12:55] Right on, and what will that give us for our equation?

Phil (Customer)
[00:13:49] x + 2 = sqrt11.5

Timothy M (Tutor)
[00:13:57] Right on.
[00:14:05] Then how would we get x all by itself?

Phil (Customer)

Timothy M (Tutor)
[00:15:35] Right on.
[00:15:41] So what does x equal?

Phil (Customer)
[00:15:54] +- sqrt11.5 - 2

Timothy M (Tutor)
[00:16:08] Right on.
[00:16:15] What did we do to solve this problem?

Phil (Customer)
[00:16:30] completing the squar
[00:16:32] *square

Timothy M (Tutor)
[00:16:44] Right on, great explanation.