## Sunday, May 8, 2011

### Hazel's Algebra Post

Algebra- writing mathematical phrases using letters to represent numbers.
Variable- a letter that represents a number in an equation or expression.
Expression- a pattern which has many possible answers. ex. 2x
Equation- Only has one possible answer. ex.
2x=6
Constant- The integer in an algebraic expression or equation

One Step Equations
1. Isolate the variable
2. Cancel using the opposite operation
- make a zero pair with the constant
3. Balance the equation
4. Verify

1. Isolate the variable

x + 2 = 5

2. Cancel

x + 2 - 2 = 5 - 2

3. Balance
x = 3

4. Verify

x + 2 = 5

3 + 2 = 5

5 = 5

Subtraction: 1.Isolate the variable

x - 1 = 3

2. Cancel

x - 1 + 1 = 3 + 1

3.Balance

x = 4

4. Verify

x - 1 = 3

4 - 1 = 3

3 = 3

Multiplication:

Inspection:

2x = 6

2x/2 = 6/2

x = 3

Verify:

2x = 6

2(3) = 6

6 = 6

Division:
Inspection:
x/2 = 3

2x/2 = 3(2)

x = 6

Verify:

x/2 = 3

6/2 = 3

3 = 3

Two Step Equations

1. Isolate

2. Cancel constant

3. Balance

4. Simplify variable

5. Balance

6. Verify

Multiplication:

2x + 1 = 5

2x + 1 - 1 = 5 - 1

2x/2 = 4/2

x = 2

2x + 1 = 5

2(2) + 1 = 5

4 + 1 = 5

5 = 5

Division
Inspection:
x/2 + 5 = 9

x/2 + 5 - 5 = 9 - 5

2x/2 = 4(2)

x = 8

Verify:

x/2 + 5 = 9

8/2 + 5 = 9

4 + 5 = 9

9 = 9