Question

What is the distance between the points (–8, –2) and (–7, –2)?

Answer 1

You subtract 7 from 8 and you get 1.
You do not subtract 2 from 2 because they are the same. You have to subtract coordinates that are not the same.
Another way to figure this out would be to plot the points on the coordinate plane and count how many spaces is in between.  

The answer is A.1<span />

Answer 2

Use the distance formula.

$\sf\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}$

(-8, -2), (-7, -2)
 x1 y1   x2 y2

$\sf\sqrt{(-7-(-8))^2+(-2-(-2))^2}$

$\sf\sqrt{1^2+0^2}$

$\sf\sqrt{1^2}$

$\sf\sqrt{1}$

$\sf~1$