Answer:
c=42.25.
Step-by-step explanation:
A perfect square is number or expression that is multiplied by to numbers or expressions to make it. So for this, you would find one number that, added with itself with make -13. Which would be -6.5. So the answer will be determined by doing (x-6.5)^2 to get x^2-13x+42.25. c = 42.25
