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Exponents and radicals


                                                      Division law of exponents
                (c)   (3 7)´  3
                                                      Consider the following example of dividing
                (d)   (2 )x 22                        exponential numbers with the same base

                                                            5
                                                                3
                (e)   (2 )t 23                        like 7 ÷ 7. The solution can be obtained


                                                      as follows:  5  5  7 =  7 5
          FOR ONLINE READING ONLY
                          23
                (f)
                      (10p
                           )
     Mathematics for Secondary Schools  (g)   5(mn ) ) 2 3 )           = 7 77 777
                                                                     3
                                                                7 ÷7 ÷
                                                                7
                                                                     3
                                                                          3
                                                                          77777´ ´ ´ ´
                         2
                      3(ab
                (h)
                                                                              ´ ´
                         3 42
                                                                       = ´
                      (2a b
                (i)
                                                                           2
                          2
                (j)
                      7x
                              7x
                             ( ) ´
                                                      Alternatively, if the bases of the numerator
                (k)   ( ) ´  (xy )(x y )  64  (7x  3   )                             =  7
                             2
                               2 2
                         4
                                                      and denominator are the same, then subtract
                           3
                                4 7
                        2
                (l)   (a m )×(a b )                   the denominator exponent from numerator
                                                      exponent.
            4.   Write each of the following          That is,
                expressions as a single exponential              5
                number:                                         7 3  =  7 5  3 -
                (a)  4  × 5 3                                   7
                       3
                                                                        7 =  2
                       17
                (b)  a  × b 17                                     7
                                                      Similarly,   a  =  aaaaaaa´´´´´´      ,
                         5
                (c)  (2a)  × a                                   a 7    aaaaaaa´´´´´´
                              5
                                                                   4
                                                                            aaaa´´´
                                                                  a
                         23
                (d)  12k  × t 23                      where  a ≠  0a  4 = = a 74 -  aaaa´´´
                (e)  2a  × b 7                                       = = a a 3 74 -
                        7
                (f)  3  × 3 4                                        =  a 3
                       2
                (g)  3  × 2 4                                     a  7
                       4
                                                      Therefore,     =  a  7  4 -  =  a  3    .
                (h)  12  × 12 21                                  a  4
                        20
                (i)  4a  × 4b 4                                      m
                        4
                (j)  5p  × 3s 3                        Generally,    x n  =  x m  n -  , where  x ≠ 0.
                        3

                                                                    x
                        5 
                       −
                (k)   q ×    1   t   − 5            That  is when exponential  numbers  of
                                                       the same base are divided, subtract
                             2                       the  exponent  of  the  divisor  from  the
                       -3
                (l)  4  × 4 5                          exponent of the dividend.
                                                    92
                                                                            Student's Book Form Two
                                                                                          11/10/2024   20:12:15
     MATHEMATIC F2 v5.indd   92
     MATHEMATIC F2 v5.indd   92                                                           11/10/2024   20:12:15
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