Respuesta :

sqdancefan
Swap x and y, then solve for y.
  x = 3y + 9
  x - 9 = 3y . . . . . . subtract 9
  (1/3)x - 3 = y . . . divide by 3

This matches the last selection
  y = 1/3x - 3

y=1/3x­-3 is the answer. 100% sure!