which expression can be used to find the length of the side of the triangle represented by the vertices (5,5) and (7,-3) on the graph?

In order to determine the correct expression for the length of the side, consider that the distance in between two points (x1,y1) and (x2,y2) is given by the following formula:
d = √((x2 - x1)² + (y2 - y1)²)
if (x1,y1) = (5,5) and (x2,y2) = (7,-3) you have for d:
d = √((7 - 5)²+(5 - (-3))²)