Find the value ofkso that the lines and are perpendicular

I got the the vector equation for both lines

L1=(x,y,z) =(4,-4,-3) + k(3,0,2)

L2=(x,y,z) (-4,-8,-12) + k(0,-2,0)

I got the dot product of (3,0,2) and (0,-2,0) and it equals zero, so it is perpendicular. I just don't know what to after