1.
If the lines 1x2=y8λ=z52\frac{1-x}{2} = \frac{y-8}{\lambda} = \frac{z-5}{2} and x115=y33=z11\frac{x-11}{5} = \frac{y-3}{3} = \frac{z-1}{1} are perpendicular, then λ=\lambda =