Logic for Formula Through C# code

Hello All,

Here I Have one Formula i want to find a logic for this through c# code

T_negative = T_0 + (T_Filtertime - 10ms) for T_Filtertime <= 100ms

T_negative = T_0 + (T_Filtertime * 0.9) for T_Filtertime > 100ms

T_negative = T_0 + (T_Filtertime - 5000ms) for T_Filtertime >= 50000ms

T_positive = T_0 + (T_Filtertime + 10ms) + (20ms + 10ms) for T_Filtertime <= 100ms

T_positive = T_0 + (T_Filtertime * 1.1) + (20ms + 10ms) for T_Filtertime > 100ms

T_positive = T_0 + (T_Filtertime + 5000ms) + (20ms + 10ms) for T_Filtertime >= 50000ms

as we see above condition i want to find both negative and positive Values