Lesson 1-3 Algebraic Expressions

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Lesson 1-3Algebraic Expressions Properties

• Objectives 9P4, 9P3
• (Do not write)
• Evaluate algebraic expressions
• Use number properties to write equivalent
  expressions

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Commutative Properties (switch elements) a b
b a a b b a
Associative Properties- (change grouping) a (b
c) (a b) c a (b c) (a b) c
Identity Properties- (keep same) a 0 a a
1 a
While these properties do not seem useful, you do
use them quite often without knowing it.
Example 1)Use the commutative and associative
properties to write an expression
equivalent to (9x 12y) 8z
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Writing algebraic expressions translate
like a foreign language any phrase with
than must reverse order less than, more than

• Example 2 Write five more than the absolute
  value of a number
• Example 3 Write 4 less than twice the sum of a
  number and 10

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Evaluate Find value ofhint follow order of
operations

• Example 4 Evaluate 3x y for x 16 and y 6
• Simplify Reduce to lowest terms
• Example 5 Simplify

316 6 54
Line flying in literally means the 1. 2/2
1 y/y 1 We are using the identity property
here!!
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Subtraction Theorem a b a (-b) can be
used either way Write equivalent expressions

• Example 6 -5x - 3y
• -5x (-3y)
• Example 7 3x 4y
• 3x-(-4y)