Answer: (D) 
Explanation:

Just a note on writing down these expressions: I recommend using parentheses whenever you can to avoid misinterpretation. An expression 1/x-1/y / 1/x+1/y could be interpreted by someone as 1/x-(1/y / 1/x)+1/y, which is a different thing.
That’s weird, it should be (-2,-7). Try (-2,7)
Answer:
D)
and
n=1
AD=7.07
Step-by-step explanation:
hope it helps