determine if any of the lines are equal or parallel

L1: (x-8)/4 = (y+5)/-2 = (z+9)/3

L2: (x+7)/2 = (y-4)/1 = (z+6)/5

L3: (x+4)/-8 = (y-1)/4 = (z+18)/-16

L4: (x-2)/-2 = (y+3)/1 = (z-4)/1.5

im not sure whether the sum is wrong... Because answer says L1 n L3 are equal. But?? how to prove it