I really need help I've gone brain dead and I only have this one left, Please help

Verify that parallelogram ABCD with vertices
A(−5,−1), B(−9,6), C(−1,5), and D(3,−2)
is a rhombus. Do the following:
Identify the diagonals of the parallelogram.
Compute the slope of each diagonal.
Explain how you know the parallelogram is a rhombus.

Graph a triangle (xyz) and reflect it over the line y=x to create triangle x’y’z’. describe the transformation using words. draw a line segment from point x to the reflecting line, and then draw a line segment from point x’ to the reflecting line. what do you notice about the two line segments you drew? do you think you would see the same characteristics if you drew the line segment connecting y with the reflecting line and then y’ with the reflecting line? how do you know?