I wrote it out on paper and uploaded the answer for you. Let me know if you have any questions.
Answer:
The answer to the question provided is y = -3x - 12.
Step-by-step explanation:
❃Incase you forgot what the linear equation formula is ☟

❃Incase you also forgot, what the slope formula is ☟

➊ First: We are going to be solving for the slope.

➋Second: We find the y-intercept.

➌Third: Plug in.

If the slope of AB = CD and BC = AD it's a parallelogram:
Slope of AB = 6+1 / -9+5 = -7/4
CD = -2-5 / 3+1 = -74
These are equal.
BC = 5-6 / -1 +9 = -1/8
AD = -2 +1 / 3+5 = -1/8
These are also equal so it is a parallelogram.
Now to find if the diagonals are perpendicular find the slope of the perpensicular points:
AC = 5 +1 / -1 +5 = 6/4 = 3/2
BD = 6+2 / -9 -3 = 8/-12 = -2/3
Because BD is the reciprocal of AC, this means they are perpendicular.
And because AB is not perpendicular to AD ( AB and AD are not reciprocals) it is a rhombus.