Idon’t understand this i don’t need an explanation can someone just me

Solve |2x - 5| = 4 if anyone could , that would be great

Monica build a remote control toy airplane for science project to test the plane she launched it from the top of a building the plane travel a horizontal distance of 50 feet before landing on the ground a quadratic function which models the height of the plane in feet relative to the ground at a horizontal distance of x feet from the building is shown

What is the distance between point a and b