Question

a point is reflected across the x-axis the new point is (-7.5,6) what is the distance between the two point

Answer 1

So if it's reflected directly across the x axis, the original point had to be (7.5,6), meaning both points are 7.5 units from the origin. since it's reflected you will add them together.
$7.5 + 7.5 = 15$
so your answer is 15 units :)