What property is this?

Answer:
x= 0/0
Step-by-step explanation:
Let's solve for x.
5x−5z=5(x−z)
Step 1: Add -5x to both sides.
5x−5z+−5x=5x−5z+−5x
−5z=−5z
Step 2: Add 5z to both sides.
−5z+5z=−5z+5z
0=0
Step 3: Divide both sides by 0.
0/0=0/0
Hope this helps ;-))