Answer:
+4sqrt(2)
Explanation:
Note that the horizontal distance is 8 - 4, or 4 (which is the "run") and that the vertical distance is -3 - (-7), or 4 (which is the "rise"). Applying the Pythagorean Theorem, we get:
distance = length of hypotenuse = +sqrt(4^2 + 4^2) = +4sqrt(2)