Answer and show the work PLS

Every weekday, mr. jones bikes from his home to his job. sometimes he rides along two roads, the long route that is shown by the solid lines. other times, he takes the shortcut shown by the dashed line. how many fewer kilometers does mr. jones bike when he takes the shortcut instead of the long route?

Idon't get undoing if its pass adding and subtracting so can someone ? x-2 over 5 = 18

Asap will give brainiest to first person to answer what is the measure of angle b in the triangle? enter your answer in the box. m∠b=