Question

please help me with this question
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Answer 1

Answer:

322

Step-by-step explanation:

sol:- first cube both (rhs) and (lhs) side of the given equation.

(X + 1/X) = 7

(X + 1/X)^3 = (7)^3

PUT FORMULA (a + b)^3

(X)^3 + (1/X)^3 + 3 × X× 1/X ( X + 1/X) = 343

(X)^3 + (1/X)^3 + 3 (7) = 343

(X)^3 + (1/X)^3 = 343 - 21

(X)^3 + (1/X)^3 = 322