Solving Two Step EquationsSolving Two Step EquationsSolving Two Step EquationsSolving Two Step EquationsObjectives: •To solve equations by using the addition and multiplication properties

How to solve two-step equations

• “Undo” the operations in the reverse order of the order of operations.

• You are using the work back-words strategy

• In order of operations we do multiplication or division first, then

addition and subtraction. When solving an equation we do the

opposite!

Solving Equations SongTune: If You’re Happy and You Know It

  

If you want to solve equations, here is how.Read them with their operations, do it now.

Then UNDO them every timeBy directions in this rhyme.

DO THE OPPOSITE. That’s what the rules allow. 

If you read “MINUS,” then to solve them you must ADD.If you say “PLUS” you must SUBTRACT or you’ll be sad.

Multiply will get undoneBy DIVIDING every one.

And divide gets MULTIPLIED, or answer’s bad. 

Oh, equations must stay balanced to be true.WHAT YOU DO TO ONE SIDE YOU MUST DO TO TWO.

And to solve for the unknown You must get it all alone

Using every single trick you know to do.

Click for music

Example 1Solve.

7x + 6 = 13-6 -67x = 77 7

x = 1

Example 2Solve.

-4y + 3 = 12 -3 -3

-4y = 9-4 -4

9y

4

4

12y

Example 3Solve.

-60 -60

9z

2 2

1410

3 2

z (6) (6) (6)

60 2 42z

2 18z

PLACEMAT EQUATION SOLVING

• Work in groups 4• Each student completes one of the

problems on the placemat. • Find the sum of the solutions and

write the sum in the center of the placemat.

• Raise hand when done.

14 7 35x

10 65

x

1.

12x 3x

20x 12x

23 193

x

1

4 5 43x

Practice

1) 9x + 6 = 51

Solve.

2) -8y – 4 = 28

3) -18 – 3x = -57

4) 4 – 8x = 12

5x 4y

13x 1x

Game• http://www.math-play.com/Two-St

ep-Equations-Game.html

Summary• When asked to solve an equation,

what is the goal?

• Which operation do you do first?