{ diff(x1, t) = 0,
  diff(x2, t) = (-1)*k17*(k1*k18*x2 - k2*x3)/k17,
  diff(x3, t) = (1*k17*(k1*k18*x2 - k2*x3) + (-1)*k3*k17*x3)/k17,
  diff(x4, t) = (1*k3*k17*x3 + (-1)*k17*(k4*x4 - k5*x5))/k17,
  diff(x5, t) = 1*k17*(k4*x4 - k5*x5)/k17,
  diff(x6, t) = (-1)*k17*(k6*k18*x6 - k7*x7)/k17,
  diff(x7, t) = (1*k17*(k6*k18*x6 - k7*x7) + (-1)*k8*k17*x7)/k17,
  diff(x8, t) = (1*k8*k17*x7 + (-1)*k17*(k9*k18*x8 - k10*x9))/k17,
  diff(x9, t) = (1*k17*(k9*k18*x8 - k10*x9) + (-1)*k17*(k11*x9 - k12*x10))/k17,
  diff(x10, t) = 1*k17*(k11*x9 - k12*x10)/k17 }