If x + 1/x = 9, what is the value of x² + 1/x²?

Algebra · Quantitative Aptitude · Medium · Practice for SSC CGL Tier 1

If x + 1/x = 9, what is the value of x² + 1/x²?

83
81
79
18

Answer and solution

Correct answer: C) 79

(x + 1/x)² = x² + 1/x² + 2, so x² + 1/x² = 9² − 2 = 79.

Learn the method: Algebra rules and worked examples · SSC CGL Tier 1 Quantitative Aptitude

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