Step-by-step explanation:
cubing both sides (p+1)^3= (7)^3
=> p^3+1/p^3+ 3(p+1/p) = 343
=> p^3+ 1/p^3 + 3(7)= 343
=> p^3+1/p^3= 343-21
=> p^3+1/p^3= 322
hope it helps
