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Algebraic Sense
Lesson 21
Evaluation and Solving
  Objectives/Vocab/Tips > Examples 1 | 2 | 3 | 4 > Practice: 1 | 2 | 3 | 4 > Reflection

Example 2:

If 5m - 9 = 41, then m is:

  1. 5
  2. 10
  3. 15
  4. 13

To solve this problem you want to use the different properties of numbers to help you as you move the numbers to find the solution.

5m - 9 = 41

5m - 9 + 9 = 41 + 9 (You want to add 9 to both sides of the equation. Adding 9 to the first side will give you -9 + 9 which equals 0 so therefore you have only 5m remaining. Remember, you want to get m by itself to find what m equals. Since you added 9 to one side of the equation you must do the same to the other side.)

5m - 0 = 50 (Using addition to find the new numbers on the two sides of the equation.)

5m = 50 (Simplify.)

5m/5 = 50/5 (In order to get m by itself you want to divide both sides by 5. The reason is because 5 divided by 5 is 1 on the first side of the equation. Then you have 1 times m which is just m, which is just what we want. Just remember to do the same to both sides of the equation, not just one side.)

m = 10 (Simply.)

Your answer to this problem is 10, which is given to you as a choice, letter B. Your answer is letter B.

Example 3 >>

 

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