## Monday, March 29, 2010

### Algebra: Equation

Introduction to Algebraic Equation

Activity 1:
Watch the movie, X finds out his value, and answer the following questions.

Given the following:
2x + 4 + x = 8 + 2(3 + x) -3
1. Is this an expression or an equation? Why?
2. What is the variable?
3. Why is an equation like a see-saw?
4. Simplify 2x + 4 + x Answer: ___________________
5. Simplify 8 + 2(3 + x) -3 Answer: ___________________
6. Solve the above for x Answer: x = ________________
Activity 2:

The objective of the activity is to use concrete representation to find the unknown variable. Algebraic reasoning is used to solve or find the numerical value of the variable.

• Levels 1 and 2 contain two scales.
• Level 3 is more difficult and has three scales.
• Your goal is to determine the weight of one or more of the objects.

Source: Math Playground (retrieved: 14 March 2010)

http://www.mathplayground.com/Algebraic_Reasoning.html

1. Activity 1:
Is this an expression or an equation? Why?
This is an equation as there is an equal sign. Expressions do not have equal signs in them.
What is the variable?
THe variable is X.
Why is an equation like a see-saw?
It is like a see-saw as the expressions on both sides of the equal sign must be equal for it to be correct.
Simplify 2x + 4 + x Answer: 3x+4
Simplify 8 + 2(3 + x) -3 Answer: 11+2x
Solve the above for x Answer: x = 7

2. Is this an expression or an equation? Why?
-Yes, it is an equation, as it has the 'equal' sign in the number sentence.

What is the variable?
-The variable is 'x'.

Why is an equation like a see-saw?
-In an equation, for it to be correct, both sides of the equation must be of the same value when compared to each other.

Simplify 2x + 4 + x Answer: 3x + 4
Simplify 8 + 2(3 + x) -3 Answer: 10 (3 + x)
Solve the above for x Answer: x = 7

3. 1. The following is actually an equation. There is an = sign to represent that the both sides of the equation is the same.
2. The variable is χ. The one and only in the following equation.
3. It is the matter of the weight of both sides on the see-saw must be equal. Similarly to an algebraic equation. Both sides must be EQUAL.
4. 2χ + 4 + χ= 3χ + 4
5. 8 + 2( 3 + χ )= 8 + 6 + χ
= 14 + χ
= χ + 14
6. 3χ + 4 = χ + 14
2χ= 14 - 4
= 10
χ= 10/2
= 5

4. 1.It is a equation as there is a equal sign.
2.It is X.
3.As both sides needs to be equal so that we can get the answer.
4.3x+4
5.11+x
6.7

5. Is this an expression or an equation? Why?
It is an equation. There is an = sign in the statement.
What is the variable?
The variable is x.
Why is an equation like a see-saw?
Each side of an equation must be equal, same as the see-saw.
Simplify 2x + 4 + x
Simplify 8 + 2(3 + x) -3
Solve the above for x

6. 1.It is an equation as there is an equal sign to show that the variables on both sides are equal.
2.The variable is x.
3.It is like a see-saw for both sides of the equation has to be equal.
4.3x+4
5.11+2x
6.x=7

7. 1. It is a equation because the equal sign is present.
2. It is X
3. the sum of one side can be greater or lesser than the sum on the other side thus, creating the effect of the rise and drop of the see-saw.
4. 3X + 4
5. 11 + 2X
6. X = 7

8. Glad to know that some students have taken the initiative to complete the task. Interestingly there are two possible values for x as found by your friends. So is x=7 or x=5? can you determine which is right and identify the error in the other.