[ Eq(Derivative(x1, t), ((-1)*k14*k4*(exp((-k13)*t)*k9 + (1 - exp((-k13)*t))*k11 + exp((-k13)*t)*k10 + (1 - exp((-k13)*t))*k12)/2*x1*x3/x5 + 1*k14*k2*x4)/k14),
  Eq(Derivative(x2, t), (1*k14*k4*(exp((-k13)*t)*k9 + (1 - exp((-k13)*t))*k11 + exp((-k13)*t)*k10 + (1 - exp((-k13)*t))*k12)/2*x1*x3/x5 + (-1)*k14*k3*x2)/k14),
  Eq(Derivative(x3, t), (1*k14*k3*x2 + (-1)*k14*k4*x3)/k14),
  Eq(Derivative(x4, t), (1*k14*k4*x3 + (-1)*k14*k2*x4)/k14),
  Eq(Derivative(x5, t), 0/k14) ]