Respuesta :

jhonyy9
use math induction proof method will be usefully 

for n=1 will get 

1^2 = 1(6*1^2 -3*1 -1)/2
1 = 1(6-4)/2
1 = 1(2)/2
1 = 1

suppose true for n=k and prove for k = k+1 

hope this will help you