Indicate the exponent of 4 on top as 1, so
every factor inside the parentheses will
have its exponent showing:



To remove the parentheses on top, multiply
each exponent inside the parentheses by
the outer exponent, 3:





To get rid of the negative exponents, 

1. Move the  from top to bottom
   and change the  exponent from
   negative to positive, so that we will have
    as a factor on the bottom.

2. Move the  from bottom to top
   and change the  exponent from
   negative to positive, so that we will have
    as a factor on the top.



To multiply the exponential factors in the 
top, add their exponents  = 

and to multiply the exponential factors in 
the bottom, add their exponents  = 



Now replace the  with 



Finally divide the 64 and the 20 both by 4



Edwin