Given: \[ x + \frac{9}{x} = 6 \] Then, \[ \frac{x^2 + 9}{x} = 6 \Rightarrow x^2 + 9 = 6x \Rightarrow x^2 - 6x + 9 = 0 \Rightarrow x^2 - 2 \cdot x \cdot 3 + 3^2 = 0 \Rightarrow (x - 3)^2 = 0 \Rightarrow x - 3 = 0 \Rightarrow x = 3 \] ∴ \[ x^2 = 3^2 = 9 \] Therefore, if \(x + \frac{9}{x} = 6\), the numerical value of \(x^2\) is 9.