Line p contains points a(–7, –9) and b(4, 0). line q is parallel to line p. line r is perpendicular to line q. what is the
slope of line r? explain.

(-7,-9)(4,0)
slope = (0 - (-9) / (4 - (-7) = 9/11...line P slope

line q is parallelparallel lines have the same slope, so line q has a slope of 9/11. 

line r is perpendicular to line qthat means line r will have a slope of -11/9. The reason is because perpendicular lines will have negative reciprocal slopes. To find the negative reciprocal of a number, just flip the number and change the sign. So, 9/11, when flipped and the sign changed is -11/9. <==