Geometry- i just need someone to check my answer!

Will give brainliest sum of arithmetic series (sigma notation) find the numerical answer to the summation given below. (image shown below)

The transitive property of equality states that: o if a = b, then bra o if a = b, then ac = bc o if a = b and b= c, then a = if a = b and c= c, then a + b = b + c

Which expression gives you the distance between the points (5,1)and(9,-6)