Let a = 2,490,103 and b = -0.02656(20)/2,490,103 (not sure if the (20) represents a multiplication)
23.1 = k - (k-a)eb
23.1 = k - keb + aeb
23.1 - aeb = k(1 - eb)
(23.1-aeb)/(1-eb) = k
Plug the values for a and b back in and compute the answer using a calculator.