def eqn_of_line(x1: float, y1: float, x2: float, y2: float) -> str:
        """
        Finds equation of a line passing through two given points.

        Parameters:
                x1, y1 : The x and y coordinates of first point
                x2, y2 : The x and y coordinates of second point

        Returns:
                Equation of the line as a string.
        """
        a = y2 - y1
        b = x1 - x2
        c = a*(x1) + b*(y1)

        if b<0:
                s=( f"{a}x - {abs(b)}y = {c}")
        else:
                s=( f"{a}x  + {b}y = {c}")
        return s