Show that 5x7^n+3+11^n-8 is always divisible by 3 for all numbers for n

Answer 1

not true for n = 1
check: 5x7^1+3+11^1-8
= 41 , which is not divisible by 3

Were there brackets ? e.g.
5(7)^(n+3) + 11^(n-8)
in that case, n≥8 or else 11^(n-8) would become a fraction.

check your typing, those brackets are crucial
I can check on my calculator for n = 8 and it is true.

Do you know how to do Induction?