From the graph, we have the following data,
Remember that the general form for the equation of a straight line is :
[tex]\begin{gathered} y\text{ = mx + c} \\ \text{where m is the slope } \\ c\text{ is the intercept on the ordinate} \end{gathered}[/tex][tex]\begin{gathered} c\text{ = 4500} \\ m\text{ = }\frac{y_2-y_1}{x_2-x_1} \\ =\text{ }\frac{0\text{ - 4500}}{9\text{ - 0}} \\ =\text{ -500} \end{gathered}[/tex]
Hence, the equation is : y = - 500x + 4500
Since Tommy lives farther than Colin, the equation that could represent his distance from London is : y = -550x + 5000, which corresponds to option D