Geometry

4.7 (2f - 0.5) = -6 (1.6f - 8.3f)

   9.4f - 2.35  = -6 (6.7f)

    9.4f - 2.35 = -40.2f

  40.2f + 9.4f = 2.35

            49.6f = 2.35

                   f = 2.35/49.6         

                     = 47/992

                     = 0.04737 #

It is nice to meet you syakirah159.  

But you need to check this answer.

1.6f - 8.3f = ????