Choose the best option to fill in the blank a(n) - is the shortest path between points on a sphere

Rewrite so the subject can be y in the formula d=m-y/y+n

Find the value of x in each case. give reasons to justify your solutions! d q ∈ pr

If a and −a are numbers on the number line, which expression must give the distance between them? a) 0 b) a c) |2a| d) |a|