15 points. picture below

Charles is on a 8 1/2 mile bike ride. he stops for a rest after he’s gone 5 2/5 miles. how much farther does he still have to go?

For what value of x does 4x = (1/8) x + 5?

Arley is building a model of a city map. in one part of the city, three roads form a right triangle, which harley draws as triangle abc, with the following measures: m∠b=90° and m∠a=30°. in his scale model, the hypotenuse of triangle abc, ac¯¯¯¯¯¯¯¯, has a length of 817−−√ cm. what is the value of a (the length of bc¯¯¯¯¯¯¯¯)?