after finishing the parallel questions, check your conjecture at this website (make sure you click the boxes in the bottom left corner so you can see the slope and equation for each line):

http://isite.lps.org/mjames2/resources/geogebra/geometry/c3_6_slope_parallel_lines.html

after finishing the perpendicular questions, check your conjecture at this website (make sure you click the boxes in the bottom left corner so you can see the slope and equation for each line):

http://isite.lps.org/mjames2/resources/geogebra/geometry/c3_7_slope_perp_lines.html