two step equations

Two-Step Equations

Using Inverse Operations

Use Inverse Operations to isolate the variable

• Inverse of addition - subtraction

• Inverse of subtraction - addition

• Inverse of multiplication - division

• Inverse of division - multiplication

Multiple Choice

What does isolate the variable mean?

• Get the variable alone

• Get rid of the variable

Our Strategy

• Keep it balanced

• What you do to one side, do to the other

• "Copy and Paste"

Multiple Choice

What is the inverse of multiplication?

• Addition

• Subtraction

• Multiplication

• Division

3x - 6 = 12

• Add 6 to both sides: 3x = 18

• Divide both sides by 3: x = 6

• Check: 3(6) - 6 = 18 - 6 = 12

What two operations are we using in this problem?

(Dividing and Adding)

Our first step is to SUBTRACT 7!!

(SADMEP--Subtract comes before Multiply)

Our second step is to MULTIPLY by 5!!

(Always do the same to BOTH sides)

Our answer is 50!!

Multiple Choice

What is the first step in solving the following equation?
3x - 5 = 20

• multiply both sides by 5
• add 5 to both sides
• divide both sides by 5
• subtract both sides by 5

Multiple Choice

2x - 8 = 6

• 3

• 8

• 7

Multiple Choice

Solve  3x - 7 = 32

• 13
• -13
• 12
• -12

Multiple Choice

4x + 7 = 23

• x = 16
• x = 4
• x = 9
• x = 12