Question 907978
Midpoint Pt(x,y):  ( {{{(x[1] + x[2])/2}}}, {{{(y[1] + y[2])/2  )}}})
R(2,5)
S(x,y) (2+x)/2 = 6, x = 10 and (5+y)/2 = 9, y = 13
S(10,13)