Explanation:
p and q are parallel.
let's first only look at a and it's intersections with p and q.
based on the rules of intersecting lines (the angles of intersecting lines are the same in both sides of any of the lines, they are only left-right mirrored) and then parallel lines at that (the intersecting angles of a line with parallel lines are the same with every parallel line, otherwise they are not parallel).
angle 2 = angle 5 = angle 10 = angle 13
therefore,
8x + 14 = 10x - 10
14 = 2x - 10
24 = 2x
x = 24/2 = 12
angle 2 = 8×11 + 14 = 88 + 14 = 102°
because of the same rules of intersecting lines and parallel lines. it is also clear that
angle 4 = angle 7 = angle 12 = angle 15
therefore,
13y + 19 = 15y + 5
19 = 2y + 5
14 = 2y
y = 14/2 = 7
angle 4 = 13y + 19 = 13×7 + 19 = 91 + 19 = 110°
if a and b would be parallel too, then the principle of the same angles would be true not only top-down (as for the pervious 2 problems) but also left-right.
and then angle 2 would be equal to angle 4.
but they are not.
although the difference is small, it means a and b will intersect somewhere.
and they are therefore not parallel.