Variable expressions

1

• Variable expressions

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Definition

• A Variable is a placeholder in a algebraic
  expression
• A Variable represents some number in a variable
  expression

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Variable

• is the Variable in the following expression

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Definition

• A Variable or Algebraic expression is a
  mathematical phrase that uses variables, numbers,
  and operation symbols

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• Special notation

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Expressions

• Is the following mathematical phrase a numerical
  expression or variable expression?

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Expressions

• Is the following mathematical phrase a numerical
  expression or variable expression?

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Objective

• Write verbal phrases as variable expressions

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Algebraic expressions

• Words that indicate mathematical operations
• (Page 5 in Book)

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• Words that indicate mathematical operations

Total More than Increased
by Difference Fewer than Less
than Decreased by Product x Times
x Quotient Divided by
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Example

• To determine your normal blood pressure divide
  your age by 2 and add 110

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Example

• Let the variable a represent age in the
  expression

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Example

• Becomes

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Evaluate

• if

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Algebraic expressions

• A number increased by 3
• Let n represent the number
• The wordsincreased by suggest addition

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Algebraic expressions

• The algebraic expression is

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Algebraic expressions

• A number divided by 8
• Let n represent the number
• The wordsdivided by suggest division

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Algebraic expressions

• The algebraic expression is

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Algebraic expressions

• The quotient of ninety-two and c
• Let c be the variable
• The word quotient implies division

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Algebraic expressions

• The algebraic expression is

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Algebraic expressions

• A number decreased by 7
• Let c be the variable
• The words decreased by imply subtraction

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Algebraic expressions

• The algebraic expression is

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Class work

• 1- 4 Practice (all)
• Jumping Cows

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Evaluate Variable Expression

• You can evaluate a variable expression by
  replacing each variable with a number
• Then use order of operations to simplify

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Variables Order of Operations

• You can evaluate a variable expression by
  replacing each variable with a number
• Do all the operations within grouping symbols
  first
• multiply and divide in order from left to right
• add and subtract in order from left to right

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Variables

• Evaluate the following
• If a 4

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Variables

• Evaluate the following
• If a 4

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Variables

• Evaluate the following
• If a 4, b 2, c 3

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Variables

• Evaluate the following
• If a 4, b 2, c 3

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Variables

• Evaluate the following
• If a 4, b 2, c 3

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Variables

• Evaluate the following
• If a 4, b 2, c 3

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Variables

• Evaluate the following
• If a 4, b 2, c 3

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