Solving Multiplication and Division Equations

Solving Multiplication and Division Equations

by Lashonda Brooks

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​Solving Multiplication and Division Equations

When solving addition and subtraction equations, there are two ideas that need to be involved...

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• 1. ​There needs to be an inverse relationship.

• ​2. Property of equality

​​Inverse Relationship

• Multiplication undergoes division.

• ​Division undergoes multiplication.

​Property of Equality

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The same value can be multiplied or divided from both sides of an equation, and equality is maintained.

How can you get the variable alone in the division equation?​

x (2) = 40​

2x = 40

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• Divide by 2 is the inverse of multiplying by 2.​

• ​SOLVE: 2x = 40

• SOLVE:  2x÷2=40÷2  --> Dividing by 2 will undo multiplying by 2. That will leave x alone.​

• ​SOLVE:  x = 40÷2  

• ​SOLVE: x = 20

​Checking Our Work:

Equation: 2x = 40

• To check, substitute 20 for x.

• 2x = 40

• 2 (20) = 40

• 40 = 40 --> It checks​

​How can you get the variable alone in the division equation?

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x÷2 = 40​

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40x÷2 = 40

• Multiply by 2 is the inverse of dividing by 2. 

• SOLVE: 40x÷2 = 40  

• SOLVE: x÷2 (2) = 40 (2)  --> Multiplying by 2 will undo dividing by 2. That will leave x alone.

• SOLVE: x = 40 (2)

• SOLVE: x = 80​

​Checking Our Work:Equation:

​x÷2 = 40 

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​To check, substitute 80 for x. 

•  40x÷2 = 40  

• 4080÷2 = 40  

• 40 = 40 --> It checks

Now It Is Your Turn!​

Remember to use the inverse relationship and the property of equality.​

Fill in the Blanks

12. Explain how to get the variable alone in the equation.

18x = 36

Fill in the Blanks

13. Explain how to get the variable alone in the equation.

 x\div3\ =10x÷3 =10  

Fill in the Blanks

14.

Solve the equation.

2t = 12

Fill in the Blanks

15.

Solve the equation.

 r÷5=22

Fill in the Blanks

16.

Solve the equation.

99 = 3x

Poll

17.

How do you feel on evaluating equations?

• Great!

• So-So.

• Confused?