To solve this equation, you could just use guess-and-check. You would just guess at values of X and keep changing your guess until you got the right answer. But this takes a lot of time! Here's a better way:

Remember in the second grade when your teacher asked you to fill in the box in a problem like this:

This

The answer to this question is 6, because 4 + 6 = 10.

Here are some simple equations:

Equation | The question it asks | The answer | Reason |
---|---|---|---|

X + 5 = 15 |
If you add 5 to my number you get 15. What is my number? |
X = 10 |
Because10 + 5 = 15 |

X - 13 = 13 |
If you subtract 13 from my number you get 13. What is my number? |
X = 26 |
Because26 - 13 = 13 |

3X = 18 |
If you multiply my number by 3, you get 18. What is my number? |
X = 6 |
Because3 times 6 = 18 |

X/4 = 5 |
If you divide my number by 4, you get 5. What is my number? |
X = 20 |
Because20/4 = 5 |

How about something more complex, like this equation:

Here's how you solve an equation of this type:

- Cover up the "2x" with your finger (I'll use a box): - 5 = 11
- Now solve for the value of the "box":

= 16 because 16 - 5 = 11 - Now look at what is in the : 2X = = 16
- Now solve the above easy equation:

X = 8, because 8 times 2 = 16

Equation | Step 1: Cover up the term with X in it |
Step 2: Solve for the boxed term |
Step 3: Look at what's in the box and solve for it |
---|---|---|---|

3X + 1 = 7 |
= 6because 6 + 1 = 7 |
X = 2, because3 times 2 = 6 | |

X/2 - 1 = 3 |
= 4because 4 - 1 = 3 |
X = 8, becauseX/2 = 4 |