Question

A line passes through (2, −1) with slope -8.

Answer 1

y - y1 = m (x - x1)

y1 being the y coordinate
x1 being the x coordinate
m being the gradient (or slope)

y - - 1 = -8 (x - 2)
y + 1 = -8x + 16
y = -8x + 15