$-1<x<0\vee x>1$

$x\le -10\vee 0\le x\le 8$

$x<0\vee 0<x\le 2$

$x<1\vee x>3$

$11.5$ ct/km

$3665$ euro

$1825+0.115a<4000$ gives you $a\le 18913$

$K\left(a\right)=2050+0.10a$ if $a<15000$; $K\left(a\right)=1825+0.115a$ if $a\ge 15000$

$a_{\text{A}}\left(t\right)=110t+24$; and $a_{\text{B}}\left(t\right)=120t$

$144$ minutes

Between $2$ hours and $2.8$ hours.

$-3\le x\le -2\vee 2\le x\le 3$

$\mathrm{-}\sqrt{13}<x<0\vee 0<x<\sqrt{13}$