4. Two marks exercise problems II

1. Let \(X = \{3, 4, 6, 8\}\). Determine whether the relation \(\mathbb{R} = \{(x, f(x)) | x \in X, f(x) = x^2 + 1\}\) is a function from \(X\) to \(\mathbb{N}\)?

 

\(\mathbb{R}\) is not a functiona function.

 

2. Let \(f(x) = 2x + 5\). If \(x \ne 0\) then find \(\frac{f(x + 2) - f(2)}{x}\).

 

\(\frac{f(x + 2) - f(2)}{x}\) \(=\)