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