1 | initial version |

Not satisfactory, but you can do:

```
sage: eq.subs({B: sqrt(17)}).subs({sqrt(17):B})
691254*B*x^15 + 397953*x^16 + 244005777*x^14
```

2 | No.2 Revision |

Not satisfactory, but you can do:

```
sage: eq.subs({B: sqrt(17)}).subs({sqrt(17):B})
691254*B*x^15 + 397953*x^16 + 244005777*x^14
```

That said, since your expressions are polynomials (they do not involve things like `log`

, `sin`

,...), you can work in a well defined polynomial ring:

```
sage: R.<B,x,y> = QQ[]
sage: R
Multivariate Polynomial Ring in B, x, y over Rational Field
sage: eq.mod(B^2-17)
691254*B*x^15 + 397953*x^16 + 244005777*x^14
```

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