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Thursday, September 12, 2013

Algebra Honors (Periods 6 & 7)

Problem Solving: Using Charts 3-6
Objective: To organize the facts of a problem in a chart.
Using a chart to organize the facts of a problem can be a helpful problem solving strategy.

Organize the given information in a chart
A swimming pool 25 m long is 13 m narrower than a pool 50 m long
There are two different charts you could create:




In the first chart we started with
Let w = the width of the 2nd pool; so to write the 1st pool in terms of the second we would place w-13 in place of the ?

In the 2nd chart we started with
Lt w = the width of the 1st pool; so we write the 2nd pool in terms of the first, so we would place w + 13 in place of that ?


We then solved the following:

Find the number of calories in an apple & a pear…

1) the pear contains 30 calories more than the apple.
2) Ten apples have as many calories as 7 pears.
Let a = the number of calories in an apple
Then a + 30 = the number of calories in a pear.
We glued in the “orange- colored” chart here and completed it to look like:






This time we reread the given facts and with the second fact, we realize that we can set
The last column expressions equal to each other
10a = 7(a + 30)
solving this equation, we find that a = 70
Therefore, an apple has 70 calories and a pear has 100 calories
Next we used the following two given facts to set up a chart and create an equation
1) An egg scrambled with butter & milk has 1 more gram of protein than an egg fried in butter.
2) Ten scrambled eggs have as much protein as a dozen fried eggs.
Let x = the number of protein in a fried egg.
Then x + 1 = the number of protein in a scrambled egg.
We glued in the “orange- colored” chart here and completed it to look like:


Our equation would be 10(x + 1) = 12x
We then turned to our textbook to Page 122-123 and completed problems 1 and 3 in our spiral notebook as follows:

Solve each problem using the two given facts. Complete a chart to help you solve each problem

1. Find the number of full 8 hour shifts that Maria worked last month
1) She worked twice as many 6 hour shifts as 8 hour shifts
2) She worked a total of 280 hours.

We also found that some problems, such as # 16 on page 124 could be easily worked out without a chart. However, the goal of this section was to attempt to use charts NOW so that in the future, using charts would help organize the information given in more complext word problems.

the Eiffe; Tower is 497 Ft taller than the Washington Monument. If each were 58 ft shorter, the Eiffel Tower would be twice as tall. How tall is each?

Let w = the height of the Washington Monument.
then Let w + 497= the height of the Eiffel Tower.
Taking the phrase " if each were 58 feet shorter" write
w -58 for the Washington Monument and (w + 497) - 58 for the Eiffel tower.
Now it states that the Riffel tower whould be twice as tall as the Washington Monument... so you would need two Washington Monuments to equal the Eiffel Tower... write an equation from that as follows
2(w - 58) = (w+497) -58

2w - 116= w + 439
w = 555
So the Washington Monument  would be 555 ft tall
and the Eiffel Tower would be 1052 ft tall

Wednesday, September 11, 2013

Algebra Honors ( Periods 6 & 7)

Equations w/ The Variable on Both Sides 3-5

Partial Notes

6x = 4x +18
You can show the steps or if it is easy you can do them in your head... However, if you make too many errors, I will suggest that you actually show the balancing steps!
x = 9
Use the set notation
{9}

3y = 15 -2y
5y = 15
{3}

(4/5)x + 3 = x
This really becomes
3 = x( 1-4/5)
or 3 = (1/5)x
12= x
{15}

How do we do a formal check:
Step 1: Rewrite the original problem
Step 2: Substitute in the solutions
Step 3: REALLY do the MATH

(4/5)x + 3 = x
(4/5)(15) + 3 = 15
12 + 3 ?=? 15
15 = 15
Hooray!

(8+x)/9 = x
We talked about the various ways to do this...
I suggested using cross products
9x = 8 + x
or 8x = 8
{1}

7(a -2) - 6 =2a + 8 + a
7a - 14 - 6 = 2a + 8 + a
combine like terms on each side FIRST
7a - 20 = 3a + 8
4a = 28
a = 7
{7}



2 unique types of equations:
Identity equation: You solve it and you get the same thing on both sides...if you solve until you cannot do anything more, you get 0 = 0.
What this means is that you can pick any number and the equation will work!
The Distributive Property is the simplest example of an Identity Equation:
3(x + 7) = 3x + 21
Distribute on the left side and you'll get:
3x + 21 = 3x + 21
At this point, you should already know this is an Identity!
If you keep solving, you would subtract 3x from each side and you'll get:
21 = 21
and you know again that this is an Identity.
If you now subtract 21 from each side:
0 = 0
BUT I WOULDN'T GO THIS FAR! AS SOON AS YOU HAVE THE SAME THING ON BOTH SIDES, YOU CAN STOP AND SAY IT'S AN IDENTITY EQUATION!!!

Null set equation:
You solve it and you get an impossible answer:
3(x + 7) = 3x + 10
3x + 21 = 3x + 10
21 = 10
WHEN WILL THAT HAPPEN??? NEVER!!! SO THERE IS NO POSSIBLE SOLUTION TO THIS! The answer is the null set.

Tuesday, September 10, 2013

Algebra Honors (Periods 6 & 7)

 Using Equations to Solve Problems 3-4

We looked at several problems in our textbook on Page 113-114
8. Find three consecutive ODD integers whose sum is 105
Let x = the first odd integer
let x + 2 = 2nd odd integer
Let x +4 = the 3rd odd integer

x + (x +2) + (x + 4) = 105
3x + 6 = 105
3x = 99

x = 33
{33, 35, 37}

10. Five consecutive integers whose sum is 195

let x = the 1st integer
x + 1 = the 2nd
x + 2 = 3rd
x + 3 = 4th
x + 4 = 5th
x + (x +1) + (x + 2) + (x + 3) + (x + 4)  =195
5x + 10 = 195
5x = 185
x = 37
{37, 38, 39, 40, 41}

12.  New tank holds 350 barrels of oil more than the old tank. Together they hold 3650 barrels of oil. How much does each hold?

Let x = the # of barrels in the old tank
let x + 350 = the # of barrels in the new tank
x + (x +350) = 3650

2x = 3300
x = 1650
The old tank holds 1650 barrels of oil
The new tank holds 2000 barrels of oil


23.  Angle A is 3 times as large as Angle B and Angle A is 16 degrees larger than Angle C

If you let x = the measure f Angel A
then
x/3 = measure of Angle B
x-16 = measure of Angle C
This became a bit complicated for some
But..
 x + (1/3)(x) + x - 16 = 180
(7/3)x - 16 = 180
(7/3)x = 196
x = 84
So Angle A is 84 degrees
Angle B is 24 Degrees
Angle C is  68 Degrees

But you could have set your variables as
Let x = the measure of Ange b
Then
3x = the measure of Angle A
3x -16 = the measure of Angle C
x + 3x + (3x - 16) = 180
x = 28
and you still get the same solutions
So Angle A is 84 degrees
Angle B is 24 Degrees
Angle C is  68 Degrees



Math 6A (Periods 1 & 2)

Problem Solving 1-6 & 1-7

Follow the 5-step plan... handed out in class.. make sure to glue it into your Spiral Notebook,

MAKE SURE TO READ and RE READ the problem!!

When you are finished--> check your work to make sure your answers make sense .
LABEL, LABEL, LABEL

Sometimes you need to use more than one operation.

Then we looked at Page 22 the Class Exercises and discussed what operations had to be used for problems # 1- 4

Make sure to check out those problems.
#2
1st OP: addition
2nd OP: division

#4
1st OP: multiplication
2nd OP: addition
We also looked at some of the even numbered word problems on Page 22
2. 18 adults $72 total for admission
To find out how much each ticket was
72/18 = 4
Mae sure to label
$4.00
The cost for each is $4.00

4. The Library had 1843 books ... after a shipment of 7 cases the total number of books at the library was 1955 books. How many new books were added to the library? We talked about the unnecessary factof 7 cases... and realized we just needed to subtract.... 1955 - 1843 = 112
They library had 112 new books.