Post on 19-Jan-2016
3/29/07 Ms. Waters
3/29/07 Ms. Waters
Objectives
• To apply the properties of equality• To simplify expressions using addition, subtraction, multiplication and division.• To solve simple multi-step equations. Sunshine State Standards
• MA.A.3.3.1• MA.D.2.3.1• MA.D.2.3.2
3/29/07 Ms. Waters
To solve two-step equations, you want to get the variable alone on one side of the equal sign using properties of equality and inverse operations.
Vocabulary:
Addition Property of Equality-If you add the same value to each side of an equation, the two sides remain equal.
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x = 7, so x + 3 = 7 + 3
x + 3 =10
3/29/07 Ms. Waters
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x = 6, so x − 4 = 6 − 4
x − 4 = 2
Subtraction Property of EqualityIf you subtract the same value from each side of an equation, the two sides remain equal. If a = b, then a - c = b - c
Vocabulary
3/29/07 Ms. Waters
Vocabulary
Multiplication Property of EqualityIf you multiply each side of an equation by the same number, the two sides remain equal.
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x =10 so, x • 5 =10• 5
x • 5 = 50
3/29/07 Ms. Waters
Vocabulary
Division Property of EqualityIf you divide each side of an equation by the same nonzero number, the two sides remain equal. If a = b, then a = b
c c
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x =16, sox
2=16
2x
2= 8
3/29/07 Ms. Waters
Lets practice the properties we just learned about.
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x = 8
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x • 2 = 8• 2
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2x =16
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2x −5 =16 −5
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2x −5 =11
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x =12
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x
6=12
6
€
x
6= 2
€
x
6+ 4 = 2 + 4
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x
6+ 4 = 6
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x = 5
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x • 3 = 5• 3
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3x =15
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3x +1=15 +1
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3x +1=16Check
Check
Check
3/29/07 Ms. Waters
Vocabulary
Inverse OperationsOperations that undo each other. - is the inverse operation of?÷ is the inverse operation of?
+x
3/29/07 Ms. Waters
The order of solving a two-step equation is the reverse of the order of operations.
First undo addition or subtraction
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2x + 3 =11
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−3 − 3
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2x = 8Then, undo multiplication or division
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2x
2=8
2
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x = 4
3/29/07 Ms. Waters
What would the previous equation look like if weused physical models to express it?
Remember:
= 0+
2x€
2x + 3 =11
€
2x
2
x = 4