Chapter 2 - Section 2.3 - Proving Lines Parallel - Exercises - Page 91: 15

Lines p and q must be parallel and lines l and n must be parallel.

Lines p and q are parallel because it is given. With this information we know that the same side interior angles 8 and 14 must be supplementary, therefore m$\angle$14 is 70$^{\circ}$. This proves that the corresponding angles 14 and 18 are congruent so lines l and n must be parallel.