Question: Factor completely over the integers. $x^4 + 4x^2 + 3$
1. **State the problem:** Factor the polynomial $$x^4 + 4x^2 + 3$$ completely over the integers.
2. **Recognize the form:** Notice that the polynomial is quadratic in terms of $x^2$. Let $y = x^2$, then the polynomial becomes $$y^2 + 4y + 3$$.
3. **Factor the quadratic in $y$:** We look for two numbers that multiply to $3$ and add to $4$. These numbers are $1$ and $3$.
4. **Write the factorization:** $$y^2 + 4y + 3 = (y + 1)(y + 3)$$.
5. **Substitute back $y = x^2$:** $$ (x^2 + 1)(x^2 + 3) $$.
6. **Check for further factorization:** Both $x^2 + 1$ and $x^2 + 3$ have no real integer factors since their discriminants are negative.
7. **Final answer:** The complete factorization over the integers is $$\boxed{(x^2 + 1)(x^2 + 3)}$$.