Can someone please help me with this? its for an important grade

What is the pattern in the values as the exponents increase?

Aperpendicular bisector, cd is drawn through point con ab if the coordinates of point a are (-3, 2) and the coordinates of point b are (7,6), the x-intercept of cd is point lies on cd.

[10 points, algebra 2-simplifying complex fractions]according to my answer key the restrictions are -1 and 4. but why not positive 1?