1. The problem statement, all variables and given/known data Find value of k so that x+2y-z=0 x+9y-5z=0 kx-y+z=0 intersect in a line 2. Relevant equations 3. The attempt at a solution multiply l1 by 5 subtract l2 from 5l1 end up with: 4x+y=0 subtract l1 from l2 end up with: 7y-4z=0 i have no idea what to do from here, or even if what i did was correct. thanks for the help.