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.