You would have to use the Pythagorean theorem to solve this.
Step 1:
-Create a triangle using point (-5,-1)
Step 2:
-Find the base and height of the triangle created.
Base=distance from (-5,0) and point A, (3,-1). (Base is 8 units)
Height=distance from (-5,0) to (-5,5). (Height is 6 units)
Step 3:
Use the Pythagorean Theorem to find the hypotenuse length which is the line segment AC.
8^2+6^2=(AC)^2
64+36=(AC)^2
100=(AC)^2
10=AC
AC is ten units long