from math import sqrt

def plug() :
   x=-100
   while x<100:
      if 2*x+5 == 13 :
         print("x = ",x)
      x+=1

def equation(a,b,c,d) :
   return((d-b)/(a-c))

   
def quad(a,b,c) :
   x1 =(-b + sqrt(b**2 -4 *a*c))/(2*a)
   x2 =(-b - sqrt(b**2 -4 *a*c))/(2*a)
   return(x1,x2)

