Kristin's Journal Entry

February 26, 2010

Today in class we learned about a negative in front of a bracket and adding and subtracting polynomials.

eg. 55x + 30 - (22x + 20) you can't leave it this way so it becomes: 55x +30 -22x - 20

A negative in front of a bracket means: the opposite of everything in the bracket.

Why? -( means -1 multiplying everything inside the bracket

Adding polynomials

- use models

(3x -4) + (2x +5) = 5x + 1- use symbols

(3x + 4) + (2x + 5)

=3x + 2x - 4 + 5

= 5x + 1

Subtracting polynomials

-use models

- add the opposite
(3x - 4) - (2x + 3)
= (3x - 4) + (-2x - 3)
= 3x - 2x -4 - 3
= x - 7

Joseph's Journal Entry

Jounel Entry Post

March, 3. 2010

Today in math class we reviewed some homework from yesterday. Next we started on a new unit on multiplying and dividing polynomials.

The first thing that we talked about is how to use algebra tiles to find out the answer to an equation. eg. (2x)(3x). To do this question using algebra tiles, you will first need to know that.....

Now that you know this, lay out your tiles as so.

Your first number in a multiplication equation will always be on the the left part of the diagram. Now just fill in the middle part of your diagram with as many x squared tiles as needed. In this case you have to add 6 x squared tiles.

The tiles in the middle of your diagram is your answer which is 6x squared.

After that we learned how to solve the same equation but algebraically this time. To solve this algebraically you just have to simply multiply both coefficients as well as the variables together to get your answer.

Next we learned how to solve division questions with algebra tiles. For this example we will use this simple question. 6x^2/3x. To solve this question lay out our tiles like this...

Notice that 3x is placed on the top of the diagram instead of the left.

The next step is very simple. Just draw as many tiles as you need so that you can multiply 3x by a certain number to get the the middle amount of tiles which is 6x^2. For this question the missing number is 2x.

To solve this question algebraically you have to divide the coefficients, and variables together. Remember that any variable without a degree will always have a degree of one. Also remember that when dividing the variables together you can subtract the exponents from both of the variables to get your answer.

Simran's Journal Entry

March 8, 2010

Today we learned a new strategy for multiplying polynomials, called "FOIL". Which stands for first, outside, inside, last.

e.g (6a-2) (6a+3)
F (6a) (6a)= 36a^2
O (6a) (3)= 18a
I (-2) (6a)= -12a
L -(2) (3)= -6

= 36a^2 + 18 -12a
= 36a^2+ 6a -6

Journal Entry

March 8, 2010

Today in class, we got our math test back. Then, we corrected some of the questions from the test that everyone had trouble with. Here's one question from the test: simplify by combining like terms:

(2c²+4)+(-c²-2)-(-3c²+4c-4)-(2c²+c+3)

c²+2+(3c²-4c+4)+(-2c²-c-3)

2c²-5c-1

Then we learned :

First

Outside

Inside

Last

It's FOIL which is used for multiplying binomials.

Here's an example:

That's all we did in class today. Now this is for homework:

-7-5 (blue sheet)

-write on your journal

-comment on the blog

Marc's Journal Entry

Hey there you guys 8D! Were supposed to make a post for the best journal entry for the past two units that we've done...I chose the entry for the test of both chapter 7 and 5, which made it so much easier.

Entry: March 19,2010 ******************(Start)

Today we basically corrected our tests. There are a few questions people had trouble with, but I'm not completley sure if they were the ones.
(^2=Squared)

19. Write a simplified expression for the area of the following figure. What is the area of this figure?
--------------------------
20. Apply the distributive property to simplify: 2x(x-4)-3x(x-4)

=2x^2-8x-3x^2+12x (combine like-terms)
=2x^2-3x^2-8x+12x
=x^2+4x
--------------------------
21. A pool table is twice as long as it is wide. If the area of the pool table is 2.88m^2, what are the dimensions of the table.

We are also to try and play a game called "Save the Zogs", in http://www.mathplayground.com/

**********************************(end)

Thank You for reading my entry, leave a comment :)

Zerlina's Journal Entry

April. 5, 2010 - Interpolation and Extrapolation (Chapter 6)

Today in class I learned how to interpolate and extrapolate. I also learned the difference between them because I honestly didn't know the difference before. Interpolating is when you are given a set of values and you estimate between them.

eg.






When x=2.5 then y=?

Interpolate the given values
y=5






Extrapolating is when you estimate a value beyond a given set of values.

eg.







When y=12 then x=?

Extrapolate beyond given values by extending the line
x=8




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