def calcStraightLine(x0, y0, x1, y1):
    """
    
    calculates the slope and the axis intercept of a straight line using to
    points in an x, y grid
    
    :Parameters:
    
    x0, y0, x1, y1: float
        2 points in an x, y grid
   
    :Returns:
    
    m, b: float 
        the slope and the axis intercept of the calculated straight line
    
    """
    m = (y1 - y0) /(x1 - x0) 
    b = (x1*y0 - x0*y1)/(x1 - x0)
    return m, b