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Answer:
(3) p^3 -3p
Step-by-step explanation:
(a +1/a) = p . . . . . . . given
(a +1/a)^3 = p^3 . . . . . . . . cube both sides
a^3 +3a^2(1/a) +3a(1/a)^2 +(1/a)^3 = p^3 . . . . . . expand
(a^3 +1/a^3) +3(a +1/a) = p^3 . . . . . . . . . . simplify, group
(a^3 +1/a^3) +3p = p^3 . . . . . . . . . . substitute p for a+1/a
(a^3 +1/a^3) = p^3 -3p . . . . . . subtract 3p from both sides
