Back to Study Guide Page

 

Back to Main Page

 

 

How to Solve Two Step Equations

 

     When you solve an equation, you are solving to find the number that is missing.  This missing number is usually shown as a letter.  You have to find the number that is missing to solve the equation.

___________________________________________

 

Rules for Solving 2-Step Equations:

 

 

Step 1:  Identify the variable.

 

          Variable-  the letter in the problem, its what you are solving for

     it can be any letter, NOT JUST X OR Y

 

       For example: 

 

                   1.  5x  +  50  =  150                                   X  IS THE VARIABLE

 

                   2.  3m +  7  =  13                              M  IS THE VARIABLE

 

 

 

          You try:  Identify the variable

 

                   1.  2x  +  18  =  36                            ___________________

 

                   2.  20  -  9n  =  27                           ___________________

 

                   3.  15t  +  5  =  100                          ___________________

 

 

Hint:  Remember that you have to get the variable by itself to find the answer!!  *

 

Step 2:  Add/Subtract whole numbers so theyre all on one side.

             ( DO IT TO BOTH SIDES OF THE = SIGN!)

 

        For example:

Text Box: Hint:  
 
Do the opposite operation that is in the equation.  
 
Here you would add + 5 to both sides of the = sign.

 

 

 


 

         

5x

-  5

=

15

 

+ 5

 

+5

5x

 

=

20

 

 

 

 

Step 3:  Multiply /Divide to get the variable by itself.

 

Text Box: Hint:  
 
Do the opposite operation that is in the equation.  
 
Here you would DIVIDE   5 to both sides of the = sign.
 

 

        For example:

 

         

5x

=

20

5

=

5

X

=

4

 

 

 

          ANSWER SHOULD BE WRITTEN:  X = 4

 

Step 4:  Check your work.

              (Do this by plugging the numbers back into the equation.

 

                5x  -  5  =  20              (5  4) 5  =  15

                                              20 5 =  15

                                             The answer is correct!  J


 

Example of How to Solve a 2- Step Equation:

 

 

  1. 8f + 4  =  20                                               

     Step 1:  Identify the variable   

                 f is the variable

                

 

     Step 2:  Add/Subtract the whole numbers to BOTH sides.

 

                  

8f

+ 4

=

20

 

- 4

 

- 4

8f

 

=

16

             

 

Step 3:  Multiply/ Divide to get the variable by itself.

              Do this on BOTH sides of the = sign.

 

        

8f

=

16

8

 

8

f

=

2

                              

ANSWER SHOULD BE WRITTEN AS:  f= 2

 

    

     Step 4:  Check your work by plugging the numbers into the equation.

 

                        8 x 2 + 4 =  20

                        16 + 4 = 20

                        J  answer is correct!!


 

Now you try:

 

Solve the following 2-Step Equations.

 

 

 

1.   3y 7 =  8

 

 

 

 

 

 

 

2.  6m + 2 =  -10

 

 

 

 

 

 

 

3.  -4f + 6 =  34

 

 

 

 

 

 

 

4.  11 + 4r  =  38

 

 

 

 

 

 

 

 

5.  -4 8x  =  36

 

 

 

 

 

 

 

 

6.  37 + 12y =  85

 

 

 

 

 

 

 

 

 

7.  5n + 2n =  42

 

 

 

 

 

 

 

 

8.  x 5  =  10

 

 

 

 

 

 

 

9.            2y 4 =  10