3.3 two step equations 1

Lesson 3.3, For use with pages 127-133

Solve the equation.

1. x – 7 = 15 2. = 12z

6

Lesson 3.3, For use with pages 127-133

Solve the equation.

1. x – 7 = 15

ANSWER 22 ANSWER 72

2. = 12z

6

Solving Multi-Step EquationsSolving Multi-Step Equations

Section 3.3Section 3.3

P. 129P. 129

Today we will learn to solve linear Today we will learn to solve linear equations using two or more equations using two or more transformations.transformations.

Again – think about “undoing” what has Again – think about “undoing” what has been done to the variable – using been done to the variable – using inverse operations!inverse operations!

Learn to solve linear equations using two or more Learn to solve linear equations using two or more transformationstransformations

Do these look familiar to you?Do these look familiar to you?

5 28

315

4

x

y


Today our equations will look more like this:Today our equations will look more like this:

Why do you think these are called two-step Why do you think these are called two-step equations?equations?

10 34

x


10 34

x

Let’s take a closer look at this equation.Focus on the variable and how the numbers are attached to the variable.Attached by “what operations?”

If I “UNDO” this equation using inverse operations, what should I undo first? Why?

““Undo” StepsUndo” Steps1) Simplify both sides1) Simplify both sides ( may include the ( may include the distributive propertydistributive property, ,

combining like terms,combining like terms,

change change subtraction to “add the oppositesubtraction to “add the opposite))

2) Addition/Subtraction transformations2) Addition/Subtraction transformations

3) Simplify3) Simplify

4) Multiplication/Division transformations4) Multiplication/Division transformations

5) Simplify5) Simplify


-2x + 5 = - 9-2x + 5 = - 9

-2x + 5 + -2x + 5 + (-5)(-5) = -9 + = -9 + (-5)(-5) Addition Addition

-2x = -14-2x = -14

-2 -2-2 -2 Division Division

x = 7x = 7

go back and check mentally – does 7 work?go back and check mentally – does 7 work?


2x – 9x + 17 = -4 keep original equ. clean2x – 9x + 17 = -4 keep original equ. clean

-7x + 17 = -4 (combine like terms)-7x + 17 = -4 (combine like terms) -7x + 17 + -7x + 17 + (-17)(-17) = -4 + = -4 + (-17)(-17) addition addition -7x = -21 simplify-7x = -21 simplify -7x = -21 division-7x = -21 division -7 -7-7 -7 x = 3 simplifyx = 3 simplify check mentally!!!check mentally!!!

Learn to solve linear equations using two or more transformationsLearn to solve linear equations using two or more transformations

21 105

w

21 105

w

21 21 10 215

w

5 11 55

w

115

w

55w

Assignment: p. 131 #3-6Assignment: p. 131 #3-6

You must show all your steps.You must show all your steps.

Just answers won’t get your problem Just answers won’t get your problem correct. correct.

Don’t forget to “CHECK” each problem!Don’t forget to “CHECK” each problem!

3.3 two step equations 1

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Transcript of 3.3 two step equations 1