def compute_slope(x1,y1,x2,y2):
    """ Computes the slope from 
    x and y co-ordinates of two points
    @x1: x-intercept of line1
    @y1: y-intercept of line1
    @x2: x-intercept of line2
    @y2: y-intercept of line2"""

    if x2!=x1:
        return ((y2-y1)/(x2-x1))