[ Eq(Derivative(x1, t), (1*k7*1/16*x1 + (-1)*k7*1/8*x1*x2 + (-1)*k7*1/32*x1**2)/k7),
  Eq(Derivative(x2, t), (1*k7*1/32*x2 + (-1)*k7*275/3200*x1*x2 + (-1)*k7*1/32*x2**2)/k7) ]