What is the equation in point-slope form of a line that passes through the points (7, −8) and (−4, 6) ?

First you differentiate to find the gradient

dy/dx = (6 - - 8) / (-4 - 7)
          = 14 / -11
          = - 14/11

Then you use this formula
y - y1 = m (x - x1)

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

y - 6 = -14/11 (x - - 4)
y - 6 = -14/11x - 56/11
y = -14/11x + 10/11