### 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?

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

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

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

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

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'

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