Find the equation, in point-slope form, of the line that passes -3 and passes through the point (1,2). plz show your work.

Substitute the given values for the parameters in the point-slope form of the equation of a line. That form is
  y - k = m(x - h)
for point (h, k) and slope m.

You have (h, k) = (1, 2) and m=-3, so your equation is
  y - 2 = -3(x - 1)