(a + b)²= a² + 2ab + b² (a - b)²= a²- 2ab + b² a² - b² = (a - b) (a + b) (a + b)³ = a³ + 3a²b + 3ab² + b³ (a - b)³ = a³ - 3a²b + 3ab² - b³ a³ + b³= (a + b) (a²- ab + b²) a³ - b³ = (a - b) (a²+ ab + b²) Questions 1. ( √3 + 1) ( √3 – 1) എത്ര? ( LD Clerk SR for ST only 2020 ) Here use identity a² - b² = (√3)² - 1² = 2 2018 1. 3.12 × 3.12 + 6.24 × 6.88 + 6.88 × 6.88 ( Caretaker Male 2018 ) Answer : 10² Here use identity (3.12+6.88)² 2. x + 1/x = 5 ആയാൽ x² + 1/x² എത്ര? ( Security Guard- Government Secretariat 2018 ) (x + 1/x) 2 = x² + 1/x² + 2 25 = x² + 1/x² +2 x² + 1/x² = 23 Previous Next
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