def intersection(x,y,z,w,r,a,b,c):
    if (r*a)+(w*b)==0:
        return None
    else :
        t=float(-a*x-b*y-c)/(r*a+w*b)
        return (x+t*w),(y+t*r)

print intersection(0,0,0,1,1,1,1,1)
print intersection(1,0,0,0,1,1,0,-3)
print intersection(0,-1,0,1,-1,1,1,1)
print intersection(0,5,0,1,1,1,0,-1)
print intersection(0,0,0,1,1,1,0,0)