Respostas

2013-03-18T18:04:40-03:00

n!/(n-2)!=20

n(n-1)(n-2)!/(n-2)!=20

n²-n-20=0

x'+x"=1
x'*x"=-20

x'=-4 < =>não existe fatorial <0

x"=5

5 3 5