given the two lines calculate the angle that is formed by the intersection of the pair of lines

L1:x=-1+3t,y=1+4t,z=-2t

L2:x=-1+2s,y=3s,z=-7+s

i have tried everything even converting these to symmetric equation and figuring out the Cartesian coordiantes for both lines which are for L1(-1,1,0) and for L2(-1,0,7)

then of course taking the dot product and dividing by the magnitude of both and the negative cosine to get the angle