Lesson: Solving Two-Step Equations with Justifications

Multiple Choice

Do you have your notebook out and ready to take notes? ​

(you will need to take a picture and upload it at the end)

• YES, I have my notebook out, I mean, I want to learn and be successful.

• Uh...No, and I know it means a bad grade, I have accepted my fate.

​Two-Step with Justifications

Objective: Solve two-step equations with justifications​

Match

WARMUP: Match the following equations with the property it illustrates.

• $$3x-1+1=4+1$$  

• $$9x+2-2=5-2$$  

• $$2\times\frac{x}{2}=-4\times2$$  

• $$\frac{5x}{5}=\frac{15}{5}$$  

Addition Property of Equality

Subtraction Property of Equality

Multiplication Property of Equality

Division Property of Equality

• Addition Property of Equality

• Subtraction Property of Equality

• Multiplication Property of Equality

• Division Property of Equality

​Properties of Equality

​VOCABULARY

​To justify a solution, students will need to be able to use appropriate mathematical language to give reasons for the particular approach used to solve a problem. Any time that a student produces a 'solution' in an attempt to solve a problem, that 'solution' needs to be justified.

​Justification

​This video has multi-step equations in it but you can see the idea and apply it to the two-step equations we are doing.

​EXAMPLE

​Solve and identify the justification used

​6x - 3 = 39

​STEPS

​JUSTIFICATION

Reorder

Reorder the justification with the problem solved.

• Given

• Addition Property of Equality

• Simplify / Combining Like Terms

• Division Property of Equality

• Simplify

1

2

3

4

5

• 1
• 2
• 3
• 4
• 5

​EXAMPLE

​Which justification is missing?

Multiple Choice

Which justification is missing?

• Addition Property of Equality

• Subtraction Property of Equality

• Multiplication Property of Equality

• Division Property of Equality

Multiple Choice

Which justification would be used for STEP 2?

• Addition Property of Equality

• Subtraction Property of Equality

• Multiplication Property of Equality

• Division Property of Equality

• Simplify