1. **State the problem:** Factor the polynomial $$P(x) = 2x^3 + 13x^2 + 3x - 18$$ given that $$(x + 6)$$ is a factor.
2. **Use the factor theorem:** Since $$(x + 6)$$ is a factor, $$P(-6) = 0$$.
3. **Perform polynomial division:** Divide $$P(x)$$ by $$(x + 6)$$ to find the quotient polynomial.
Set up the division:
$$\frac{2x^3 + 13x^2 + 3x - 18}{x + 6}$$
4. **Divide the leading terms:** $$\frac{2x^3}{x} = 2x^2$$.
Multiply back: $$2x^2(x + 6) = 2x^3 + 12x^2$$.
Subtract:
$$\begin{aligned}
(2x^3 + 13x^2) - (2x^3 + 12x^2) &= 13x^2 - 12x^2 = x^2
\end{aligned}$$
Bring down the next term: $$+ 3x$$.
5. **Next division:** $$\frac{x^2}{x} = x$$.
Multiply back: $$x(x + 6) = x^2 + 6x$$.
Subtract:
$$\begin{aligned}
(x^2 + 3x) - (x^2 + 6x) &= 3x - 6x = -3x
\end{aligned}$$
Bring down the next term: $$- 18$$.
6. **Next division:** $$\frac{-3x}{x} = -3$$.
Multiply back: $$-3(x + 6) = -3x - 18$$.
Subtract:
$$\begin{aligned}
(-3x - 18) - (-3x - 18) &= 0
\end{aligned}$$
7. **Quotient polynomial:** $$2x^2 + x - 3$$.
8. **Factor the quadratic:** Find factors of $$2x^2 + x - 3$$.
Look for two numbers that multiply to $$2 \times (-3) = -6$$ and add to $$1$$.
These numbers are $$3$$ and $$-2$$.
Rewrite:
$$2x^2 + 3x - 2x - 3$$
Group:
$$(2x^2 + 3x) - (2x + 3)$$
Factor each group:
$$x(2x + 3) - 1(2x + 3)$$
Factor out common binomial:
$$(2x + 3)(x - 1)$$
9. **Final factorization:**
$$P(x) = (x + 6)(2x + 3)(x - 1)$$
This is the fully factored form of the polynomial.
Polynomial Factorization A2485A
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.