<< Graphics`Graphics`

DisplayTogether[Plot[0.8 k - 1, {k, 0, 1.5}], 
      Plot[4 k - 1, {k, 0, 0.5}], Plot[Exp[-2 k], {k, 0, 1.5}], 
      Plot[-Exp[-2 k], {k, 0, 1.5}], 
      ImageSize -> 550]