This entire quiz is going to be the end of me.

Given points (-5,-1) and (5,9):
Let (x1,y1) = (-5,-1)
(x2,y2) = (5,9)

Use the following distance formula:

d = √[(x2 - x1)^2 + (y2 - y1)^2]

d = √[(5 — (-5))^2 + (9 — (-1))^2]

d = √[(5 + 5)^2 + (9 + 1)^2]

d = √[(10)^2 + (10)^2]

Add similar elements:

d = √[(10)^2 • 2]

The squared root of 10^2 is 10, so it goes outside the square root:

d = 10 √2

Therefore, the correct answer is Option 3:
d = 10 √2

Hope this helps :)