Math 7 ( Period 4)

Solving Multi Step Equations 4.2

Before you use inverse operations to solve an equation, you should check to see whether ONE or BOTH sides of the equation can be simplified by combining like terms!

2x + 3x - 4 = 11

5x -  4 = 11   ( Combine like termsà 2x + 3x = 5x)

we used the  addition property of equality ( +  prop=)

5x + 0 = 15    
Here we have the Additive Inverse or Inverse Property of Addition  (Inv +)

We don’t want to write with “+ 0”

The Identity property of Addition (ID+) allows us to write

5x = 15

Now we need to divide both sides by 5 and the Division Property of Equality ( ÷ prop =)  allows us to do that

5x/5 = 15/5  Multiplicative Inverse or the Inverse Property of Mult (Inv×)

1x = 3  we don’t want to write 1x ->Using the Identity Property of Multiplication (ID×)

x = 3 
and we BOX our answer.

Solving

-13 = 3n + 3 + n

Involves a similar process:

we need to combine like terms first

-13 = 4n + 3 ( combining 3n + 1n= 4n)

  we used the Subtraction Property of Equality ( -prop=)

-16 = 4n +0   
Here we have the Additive Inverse or Inverse Property of Addition  (Inv +)

We don’t want to write with “+ 0”

The Identity property of Addition (ID+) allows us to write

-16 = 4n

Now we need to divide BOTH sides by 4 and the Division Property of Equality (÷prop=) allows us to do that.

-16/4 = 4n/4   

Multiplicative Inverse or the Inverse Property of Mult (Inv×)

-4 =1n   we don’t want to write 1x ->Using the Identity Property of Multiplication (ID×)

-4 = n  

and we BOX our answer.