If the function `f: R->R` be defined by `f(x)=x^2+5x+9` , find `f^(-1)(8)` and `f^(-1)(9)` .

Explanation

To find \( f^{-1}(8) \) and \( f^{-1}(9) \) for the function \( f(x) = x^2 + 5x + 9 \), we first need to determine if the function is bijective (both injective and surjective). If it is not bijective, the inverse function does not exist.

### Step 1: Check if the function is bijective

1. **Find the derivative**:
\[ f'(x) = 2x + 5 \]
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