The general equation for exponential decay characterized by a half-life (T) is expressed as N(t) = N_0(1/2)^(t/T), where N(t) signifies the amount remaining at time t, N_0 stands for the initial amount (at t=0), and T denotes the half-life of the substance. The half-life of carbon-14 is about 5,730 years. When starting with 6 mg of carbon-14, the equation for the remaining amount after t years would be established.