Question 751493
 two vertex of triangle are  (1,-5) and (5,1) median intersect at (1, -1)
let third vertex of triangle is (x,y)
mid point side (1,-5) and (5,1)  where median  meet is  5+1/2=3    and  -5+1/2=-2
medians of triangle intersect at the ratio of 2:1
by using section formula 
we can say 1= 2 multiplied 3+x/3 
           3=6+x
x=-3
similarly
-1=-2 multiplied -2+y/3
-3=-4+y
y=1
 third vertex  will be   (-3,1)
answer     (-3,1)