Question: how do you factor $12x^3 - 15x^2 + 2$
1. **State the problem:** We want to factor the polynomial $$12x^3 - 15x^2 + 2$$.
2. **Look for common factors:** Check if there is a greatest common factor (GCF) among the terms.
3. The terms are $12x^3$, $-15x^2$, and $2$. The coefficients are $12$, $-15$, and $2$. The GCF of $12$, $15$, and $2$ is $1$, and the variable $x$ is not common to all terms (since $2$ has no $x$).
4. Since there is no common factor other than $1$, we cannot factor out a GCF.
5. **Try factoring by grouping or other methods:** Since this is a cubic polynomial with three terms, try to factor it as a product of a linear and a quadratic polynomial:
$$12x^3 - 15x^2 + 2 = (ax + b)(cx^2 + dx + e)$$
6. Expand the right side:
$$ (ax + b)(cx^2 + dx + e) = acx^3 + adx^2 + aex + bcx^2 + bdx + be $$
Group like terms:
$$ acx^3 + (ad + bc)x^2 + (ae + bd)x + be $$
7. Match coefficients with the original polynomial:
$$ ac = 12 $$
$$ ad + bc = -15 $$
$$ ae + bd = 0 $$ (since there is no $x$ term in the original)
$$ be = 2 $$
8. Try integer factors for $a$, $c$, $b$, $d$, $e$ that satisfy these equations.
9. After testing possible integer combinations, no integer factorization satisfies all conditions.
10. **Conclusion:** The polynomial $$12x^3 - 15x^2 + 2$$ does not factor nicely over the integers.
Therefore, the polynomial is prime over the integers and cannot be factored further using integer coefficients.