Hope this helps but I think it is A.)addition property of equality.
Answer: 6
Step-by-step explanation: So there is 4 people and lets say I'm one of them, so I shake hands with 3 people, that's 3 handshakes, then one of those 3 people shake hands with the other 2, that's 5 handshakes, and then the last 2 shake hands with each other since they haven't, so that's 1 more which means 6 handshakes.
Sorry if this is wrong.
Answer:
i beileve the answer is 10
X2-64=0
x2=64
x=8 because when multiplied by itself, and plugged back in, it works
