1. **State the problems:**
We have two problems to solve:
- Simplify the expression $(3x + 2y)(3x - y)$.
- Simplify the rational expression $\frac{n + 2}{n^2 - n - 6}$.
2. **Simplify $(3x + 2y)(3x - y)$:**
Use the distributive property (FOIL method) to expand:
$$
(3x + 2y)(3x - y) = 3x \cdot 3x + 3x \cdot (-y) + 2y \cdot 3x + 2y \cdot (-y)
$$
Calculate each term:
$$
= 9x^2 - 3xy + 6xy - 2y^2
$$
Combine like terms $-3xy + 6xy = 3xy$:
$$
= 9x^2 + 3xy - 2y^2
$$
3. **Simplify $\frac{n + 2}{n^2 - n - 6}$:**
First, factor the denominator:
$$
n^2 - n - 6 = (n - 3)(n + 2)
$$
Rewrite the expression:
$$
\frac{n + 2}{(n - 3)(n + 2)}
$$
Cancel the common factor $n + 2$ (assuming $n \neq -2$):
$$
\frac{\cancel{n + 2}}{(n - 3)\cancel{(n + 2)}} = \frac{1}{n - 3}
$$
4. **Final answers:**
- $(3x + 2y)(3x - y) = 9x^2 + 3xy - 2y^2$
- $\frac{n + 2}{n^2 - n - 6} = \frac{1}{n - 3}$ (valid for $n \neq -2, 3$)
Expression Simplification B5Ce78
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.