Resposta :
[tex]\Large\boxed{\begin{array}{l}\sf d(x)=50x+6\\\tt a)~\sf d(10)=50\cdot 10+6\\\sf d(10)=506\,km\\\tt b)\sf d(x)=1306\\\sf 50x+6=1306\\\sf 50x=1306-6\\\sf 50x=1300\\\sf x=\dfrac{1300}{50}\\\\\sf x=26\,h\end{array}}[/tex]
[tex]\Large\boxed{\begin{array}{l}\sf d(x)=50x+6\\\tt a)~\sf d(10)=50\cdot 10+6\\\sf d(10)=506\,km\\\tt b)\sf d(x)=1306\\\sf 50x+6=1306\\\sf 50x=1306-6\\\sf 50x=1300\\\sf x=\dfrac{1300}{50}\\\\\sf x=26\,h\end{array}}[/tex]