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Introduction to Algebra (PDF)

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        Introduction to Algebra
All math problems are “Algebra” because there is always at least one “unknown” in every
problem. Even 2 + 3 = ___ is an Algebra problem.

Ex: 2 + 3 = y                             y=5

In Algebra the unknown variable doesn’t just come at the end of a problem, it can be
anywhere. To find y it must be isolated from the rest of the problem.

                                                 Tips

                    1. To remove positive numbers, subtract them from both sides.
                                                                     Remember, if you do it to one
Ex: 2 + y = 5                                    2 + y = 5           side of the equation, you must
                                                -2       -2          do it to the other!
                                                     y= 3

                       2. To remove negative numbers, add them to both sides.

                                                                     Remember, if you do it to one
Ex: y - 7 = 5                                   y - 7 = 5
                                                                     side of the equation, you must
                                                  + 7 +7             do it to the other!
                                                     y = 12


        3. To remove numbers multiplied by the unknown, divide both sides by that number.
                                                                         Remember, if you do it to one
Ex: 3   x   a = 6                               3   x a = 6              side of the equation, you must
                                                    3     3              do it to the other!
                       Dividing by 3 is the
                       same as multiplying
                                                        a = 2
                       by (1/3)!
        4. To remove numbers divided by the coefficient, multiply both sides by that number.

                                                                         Remember, if you do it to one
  Ex:        a = 10                             5   x    a = 10
                                                                         side of the equation, you must
             5                                           5    5          do it to the other!


                                                         a = 2

  When more than one operation is required, first deal with any adding/subtracting and then
  deal with multiplying and dividing.
                                                                  First add or subtract any
Ex: 2   x   b + 6 = 12                 2   x   b + 6 = 12
                                                                  necessary numbers.
                                                   -6   -6
                                                2 x b = 6
                                                  2     2
                                                                  Then multiply or divide
                                                                  any coefficients.
                                                        b = 3

				
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Description: A review of the basics of solving for an unknown in Algebra you can use to help your kids with their homework.
Cate O'Donnell Cate O'Donnell http://
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