-8x -2y = 16
Algebraically rearrange into the form ' y = mx + c'.
Hence
2y = -8x - 16
Divide both sides by '2'
y = -4x - 8
Hence
'm' the slope is '-4'
'c' the y-intersect is '-8'.
NB The equation can be in numerous forms : -
-8x - 2y - 16 = 0
8x + 2y + 16 = 0
-8x = 2x + 16