1. Do Now 10/5/11
In your notebook, define the word “collect”. Do you “collect” anything? If so what?

2. Objective
2.3 simplify variable expressions

3. Section 2.3 “Simplifying Variable Expressions”
Parts of an Expression
Coefficient
the number part
of a variable term
-3x + 2x + 8
Terms
of the expression are separated by addition signs
Constant
term that has
no variable

4. Simplifying an Expression
Like Terms
terms that have
The same variable
-3x + 2x + 8
-3x + 2x + 8
You can simplify an expression by COLLECTING LIKE
TERMS
-1x + 8

5. Simplifying an Expression
The coefficient is always 1 for a variable with no number in front of it.
4n – 7 – 1n + 9
4n – 7 – n + 9
4n + (-7) + (-1n) + 9
Write expression as a sum
“Opp-Opp”
4n + (-1n) + (-7) + 9
Commutative Property
3n + 2
COLLECT LIKE TERMS

6. Parts of an Expression 7x² + 5x + 8 + 3x
1) List the terms of the expression.
7x², 5x, 8, 3x
2) List the coefficients of the expression.
7, 5, 3.
3) List the like terms of the expression.
5x and 3x
4) List the constant terms of the expression. 8
5) Simplify the expression.
7x² + 8x + 8

7. Simplify the Expression
A). 10a + 2b
3a + 2b + 7a
5b² b²
2x – – 3x
D. x + y – 12y – 3x
B). 15b² + 7
C). -x + 9 or
-1x + 9
D). -2x + (-11y) or
-2x – 11y

8. Simplifying Expressions in Geometry
What is the perimeter of the trapezoid?
Perimeter is the
distance around a figure. 3x
Add together each of the sides.
x + 2
x + 2
x x + x x
(reorder terms)
x + 3x + x + 5x
(combine like terms) 5x
10x + 4

9. Find the Perimeter of the Figure
4 + 2w w
Challenge
What is the area of the figure?
Perimeter = 2(L) + 2(W)
Area = length x width
Perimeter = 2(w) + 2(4 +2w)
Area = (w)(4 + 2w)
Perimeter = 2w w)
= 6w + 8
Area = 4w + 2w²