1. Use the vertical line test to decide whether graphs \( A, B \), or both represent functions. Which of the graphs is a function? B Both Neither

\[ f(x)=\frac{|x|}{x}=\left\{\begin{array}{lr}3 x-1, & x>3, \\ \mathrm{x}^{2}-2, & -2 \leq x \leq 3 \\ 2 x+3, & x<-2,\end{array}\right. \] d the values of \( f(2), f(4), f(-1), f(-3) \) and \( \mathrm{f}(0) \).

\( \min (z)=2 x 1+3 x 2 \) s.t: \( : x 1-2 x 2 \leq 4 \) \( x 1-x 2 \geq 3 \) \( x 1, x 2 \geq 0 \)

ค่าของ \( P_{6,1}-C_{8,2}+P_{7,3} \) มีค่าตรงกับข้อใด 188 240 120 720

If \( R \) is a relation \( { }^{\prime}<{ }^{\prime} \) from \( A=\{1,2,3,4] \) to \( B=\{1,3,5\} \). i.e. \( (a, b) \in R \) if and only if \( x<b \), then find \( R \circ R^{-1} \). solution:

\[ f(x)=\frac{|x|}{x}=\left\{\begin{array}{lr}3 x-1, & x>3, \\ \mathrm{x}^{2}-2, & -2 \leq x \leq 3 \\ 2 x+3, & x<-2,\end{array}\right. \] d the values of \( f(2), f(4), f(-1), f(-3) \) and \( \mathrm{f}(0) \).