[ Eq(x11, x5 + x10),
  Eq(x12, x2 + x3 + x4 + x6 + x7 + x8 + x9),
  Eq(1*k17*x2 + 1*k17*x3 + 1*k17*x4 + 1*k17*x5, k17*k19),
  Eq(1*k17*x6 + 1*k17*x7 + 1*k17*x8 + 1*k17*x9 + 1*k17*x10, k17*k20) ]