[ Eq(1*k6*x2 + 1*k6*x3 + 1*k6*x6, k6*k88),
  Eq(1*k6*x8 + 1*k6*x9, k6*k89),
  Eq(1*k7*x11 + 1*k7*x12 + 1*k7*x13, k7*k90),
  Eq(8*k7*x11 + 4*k7*x12 + 4*k7*x14 + 4*k7*x15 + 8*k7*x16 + 4*k7*x17 + 4*k7*x18 + 4*k7*x21 + 4*k7*x22, k7*k91),
  Eq(1*k7*x19 + 1*k7*x20, k7*k92) ]