LOGARITHMS B24

Evaluate the following giving your answer in standard form.

78.7 x 10^-9

   5 x 10^-20

Solution

=  78.7 x 10^-9

       5 x 10^-20

=  78.7  x   10^-9

       5         10^-20

=  15.74 x 10^{-9 –(-20)}

=  15.74 x 10^{-9 + 20}    

=  15.74 x 10¹¹      then we change 15.74 into standard form as well

= 1.574 x 10¹ x 10¹¹   when we have exponents with same base, we add the

                                    Powers.

= 1.574 x 10¹⁺¹¹

= 1.574 x 10¹²

Hence   78.7 x 10^-9   = 1.574 x 10¹²

                 5 x 10^-20

TRY THIS..............

Evaluate the following giving your answer in standard form.

456.9 x 10^-8

   5 x 10^-30