Answer: C
\(9x^2 - 13x + 9 = 0\) i.e., \(9x^2 + 9 = 13x\) i.e., \(9(x^2 + 1) = 13x\) i.e., \(\cfrac{x^2 + 1}{x} = \cfrac{13}{9}\) i.e., \(x + \cfrac{1}{x} = \cfrac{13}{9}\)
\(9x^2 - 13x + 9 = 0\) i.e., \(9x^2 + 9 = 13x\) i.e., \(9(x^2 + 1) = 13x\) i.e., \(\cfrac{x^2 + 1}{x} = \cfrac{13}{9}\) i.e., \(x + \cfrac{1}{x} = \cfrac{13}{9}\)