SSC CHSL 2023 · Question 52 of 92
Algebra
Given: x + 1/x = 5 Formula used: (a + b)2 = a2 + 2ab + b2 (a + b)3 = a3 + 3ab(a + b) + b3 Calculation: x + 1/x = 5 ⇒ x2 + 1/x2 = 52 – 2 ⇒ 23 x3 + 1/x3 ⇒ 53 – 3(5) ⇒ 125 – 15 ⇒ 110 x5 + 1/x5 = (x2 + 1/x2)( x3 + 1/x3) – (x + 1/x) ⇒ 23 × 110 – 5 ⇒ 2530 – 5 ⇒ 2525 ∴ x5 + 1/x5 is 2525.
Source: SSC CHSL 2023 (Tier-I) Previous Year Paper (07-Aug-2023) (Shift 2) — prepp.in · reliable-secondary
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