9. The quadratic equation whose one rational root is 3 + √2 is (a) x² – 7x + 5 = 0 (b) x² + 7x + 6 = 0 (c) x² – 7x + 6 = 0 (d) x² – 6x + 7 = 0

Answer: d Explaination:Reason: ∵ one root is 3 + √2 ∴ other root is 3 – √2 ∴ Sum of roots = 3 + √2 + 3 – √2 = 6 Product of roots = (3 + √2)(3 – √2) = (3)² – (√2)² = 9 – 2 = 7 ∴ Required quadratic equation is x² – 6x + 7 = 0