Let X,Y and Z be points such that \(\frac{XZ}{XY} = \frac{ZY}{XY} = \frac{1}{2}.\)If Y=(1,7), Z=(-1,-7), then what is the sum of the coordinates of X?
Based in the question, it is to see that point Z is the midpoint of line XY.
(x+1) / 2 = -1 x+1=-2, x=-3
(y+7) / 2 = -7, y+7=-14, y=-21
(-3,-21)
+223 
