ꯀꯔꯤꯒꯨꯝꯕꯥ $x + \dfrac{1}{x} = 5$ ꯑꯣꯏꯔꯕꯗꯤ, $x^3 + \dfrac{1}{x^3}$ ꯊꯤꯌꯨ꯫
A$110$
B$125$
C$105$
D$100$
Answer & Solution
Correct answer: A. $110$
$(x+1/x)^3=x^3+1/x^3+3(x+1/x)$ ꯁꯤꯖꯤꯟꯅꯗꯨꯅꯥ ꯑꯩꯈꯣꯌꯅꯥ $125=x^3+1/x^3+15$ ꯐꯪꯏ꯫ ꯃꯔꯝ ꯑꯁꯤꯅꯥ $x^3+1/x^3=110$, ꯃꯔꯝ ꯑꯗꯨꯅꯥ ꯑꯣꯄꯁꯟ A ꯑꯁꯤ ꯑꯆꯨꯝꯕꯅꯤ꯫ ꯑꯣꯄꯁꯟ B, $125$, ꯑꯁꯤ ꯀ꯭ꯔꯣꯁ-ꯇꯔꯝ $15$ ꯂꯧꯊꯣꯀꯄꯗꯒꯤ ꯊꯣꯀꯏ꯫
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