    ### Solving Equations − Addition and Subtraction 1

Solving equations involves finding the value of an unknown variable. This is done by inversing − a process that reverses the equation. Let us take a look

The inverse of addition is subtraction and the inverse of subtraction is addition

• #### Example 1.   6 + b = 14   What is the value of b?

• The inverse of 6 is − 6. So subtract 6 from both sides

 6 + b = 14 − 6 = − 6

 b = 8

To verify, put the value of b = 8 back into the original equation
6 + 8 = 14

• #### Example 2.   a − 12 = 5   What is the value of a?

• The inverse of − 12 is + 12. So add 12 to both sides

 a − 12 = 5 + 12 = + 12

 a = 17

To check, put the value of a = 17 back into the original equation
17 − 12 = 5

• #### Example 3.   50 + d = −30   What is the value of d?

• The inverse of 50 is − 50. So subtract 50 from both sides

 50 + d = −30 − 50 = −50

 d = −80

To verify, put the value of d = −80 back into the original equation
50 + ( −80 ) = 50 − 80 = −30

#### Note: 'what is the value of y' is the same as 'solve y' to:  