We have the following:
The first thing is to calculate the equation by means of the graph.
For Andrew, we can see that he starts at $ 3 and every hour that passes, he charges $ 2, therefore the equation is:
[tex]y=3+2x[/tex]
where x is the number of hours.
For Dave, we can see that he starts at $ 6 and every hour that passes, he charges $ 1.5, therefore the equation is:
[tex]y=6+1.5x[/tex]
where x is the number of hours.
to calculate the number of hours when the value is equal, we must match the equations like this
[tex]\begin{gathered} 3+2x=6+1.5x \\ 2x-1.5x=6-3 \\ 0.5x=3 \\ x=\frac{3}{0.5}=6 \end{gathered}[/tex]
Which means that at 6 hours they have the same price
