Left:
180-53 = (8x-9)
127+9 = 8x
136 = 8x
x = 17
Right:
(15x+29) = (26x-4)
29+4 = 26x-15x
33 = 11x
x = 3
Because we're given two points on the line, we can apply the slope formula to find the answer:

-4 - 8 / 2 - (-1)
-12 / 3
-4
<h3>The slope of the line is -4.</h3>