Which is an equation of the line that passes through the points (5 15) and (10 20)?

The generic equation of the line is:
 y-yo = m (x-xo)
 Where,
 m = (y2-y1) / (x2-x1)
 Substituting values:
 m = (20-15) / (10-5)
 m = (5) / (5)
 m = 1
 We choose an ordered pair:
 (xo, yo) = (5, 15)
 Substituting values:
 y-15 = 1 (x-5)
 y = x - 5 + 15
 y = x + 10
 
 An equation of the line that passes through the points (5 15) and (10 20) is:
 y = x + 10