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(b)  Application of equality concept

                   2x + 1 = 7               x x






                   2x + 1  – 1  = 7  – 1    x x                                In a linear equation, the
                                                                               value on the left hand
                                                                               side is always equal to
                                                                               the value on the right
                   2x = 6                   x x                                hand side. Therefore, the
                                                                               mathematical operations
                                                                               performed on both sides
                                                                               of the linear equation
                                                                               must be the same
                    2x    6                                                    in order to obey the
                       =
                    2     2                  x   x                             equality concept.
       CHAPTER
       6

                   Thus, x = 3                 x








               (c)  Backtracking method
                   2x + 1 = 7
                   Let the initial value = x and the final value = 7.
                   List the mathematical operations starting from the value    The backtracking method
                   of x to become 7.                                           uses working backwards
                                                                               strategy and usually is
                   x        × 2        + 1      = 7                            used to solve problems
                                                                               that have known final
                   By using backtracking method, we have to consider the       value but the initial value
                   reverse operation so that 7 can become the value of x.      is unknown.
                   x        ÷ 2        – 1      = 7

                   So the value of x can be determined by writing

                   7 – 1 = 6       6 ÷ 2 = 3

                   Thus, x = 3       In the backtracking method,                Is backtracking method
                                     the order of mathematical
                                     operations is very important.              appropriate for solving
                                                                                all the linear equations?
                                                                                Discuss.


           128
           Chapter 6



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