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 $\frac{f(x + 2) - f(2)}{x}$.

 

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