Question

Va rog sa ma ajutati..
(n+1)!+n!=144 si n!+(n+1)!>8n×(n-1)!​ Dau coroana!!

Answer 1

a)

n!*(n+1)+n!=144

n!(n+2)=144=12*12=3*4*2*6=2*3*4*(4+2)=4!(4+2) deci n=4

b)

n!+(n+1)!>8n×(n-1)!​

⇔n·(n-1)!​ +(n+1)·n·(n-1)!​ >8n×(n-1)!​

⇔1+n+1>8

⇔n>6