Answer: 15.0 units.
Explanation:
The distance between two points A (a,b) and B (c,d) is given by :-

Given points : C=(7 -4) and D=(-8,-5)
Now, the distance between two points C=(7 -4) and D=(-8,-5) will be :-

Hence, the distance between C=(7 -4) and D=(-8,-5) is CD = 15.0 units.