need help

• tofushop193

  22 Apr 09, 16:16

  (20^n)(5^1-n)

  ___________

       4^1+n

  how do u get 5/4???
• kilfer

  22 Apr 09, 16:29

  Step 1) Original

  (20^n)(5^1-n)

  ___________

       4^1+n

  Step 2) Expand

  (4^n x 5^n) x (5 / 5^n)

  __________________

             4 x 4^n

  Step 3) Take out 4^n / 4^n

  5^n(5 / 5^n)

  __________

           4

  Step 4) Take out 5^n / 5^n

  5

  _

  4

   
• tofushop193

  22 Apr 09, 20:33

  how come expend like that already?as in

  (20^n)(5^1-n) how to become (4^n x 5^n) x (5 / 5^n)

  and

  4^1+n how to become 4 x 4^n

• dkcx

  22 Apr 09, 20:52

  4^n X 5^n = (4X5)^n = 20^n

  4^(1+n) = 4^1 X 4^n = 4X4^n