C1 = 200; 
C2 = 100; 
Roots[
      C2 (-0.5 (T^2) + 2 T  -  0.5) - (C1 + 
                C2 (T - 1)) (-T + 2) == 0, 
      T]

Cost[
          T_] := ((C1 + C2 (T - 1))/(-0.5 (T^2) + 2 T - 0.5));

Cost[1.449]

Cost[2]