Respostas

2013-06-19T19:15:32-03:00

a) 8!/4!2! = 8.7.6.5.4!/4!.2 =8.7.6.5/2 = 4.7.6.5 = 30.28 = 840

 

a) (x+2)(x+1)(x)! / x . (x-1)! .6 = x! / (x-1)!

     (x+2)(x+1) / 6x = 1

     x²-3x+2=0

      x = 2 e x = 1

4 4 4