1. **State the problem:** Simplify the expressions:
a) $\frac{6^n + 3^n}{2^{n+1} + 2}$
b) $\frac{12^x + 1}{6^{2x} + 3^x}$
2. **Recall useful rules:**
- Exponent rules: $a^{m+n} = a^m \cdot a^n$, $\left(a^m\right)^n = a^{mn}$
- Factorization: look for common bases or terms.
3. **Simplify (a):**
Numerator: $6^n + 3^n$
Denominator: $2^{n+1} + 2 = 2 \cdot 2^n + 2 = 2(2^n + 1)$
Rewrite numerator:
$6^n = (2 \cdot 3)^n = 2^n \cdot 3^n$
So numerator = $2^n 3^n + 3^n = 3^n (2^n + 1)$
Expression becomes:
$$\frac{3^n (2^n + 1)}{2 (2^n + 1)}$$
Cancel common factor $2^n + 1$:
$$\frac{3^n \cancel{(2^n + 1)}}{2 \cancel{(2^n + 1)}} = \frac{3^n}{2}$$
4. **Simplify (b):**
Numerator: $12^x + 1$
Denominator: $6^{2x} + 3^x$
Rewrite terms:
$12^x = (6 \cdot 2)^x = 6^x \cdot 2^x$
$6^{2x} = (6^x)^2$
So denominator = $(6^x)^2 + 3^x$
Also, $3^x = (6^{x})^{\log_6 3}$ but better to express $3^x$ as is.
Notice $3^x = (3)^x$ and $6^x = (2 \cdot 3)^x = 2^x 3^x$
Let's rewrite denominator:
$6^{2x} + 3^x = (6^x)^2 + 3^x$
Substitute $6^x = 2^x 3^x$:
Denominator = $(2^x 3^x)^2 + 3^x = 2^{2x} 3^{2x} + 3^x$
Factor $3^x$ from denominator:
$3^x (2^{2x} 3^x + 1) = 3^x (2^{2x} 3^x + 1)$
Numerator is $12^x + 1 = 6^x 2^x + 1 = 2^x 3^x 2^x + 1 = 2^x 3^x 2^x + 1$ (rewriting is complex, better to keep as $12^x + 1$)
Alternatively, rewrite numerator as $12^x + 1 = (12)^x + 1$
Let's try to factor denominator differently:
Denominator: $6^{2x} + 3^x = (6^x)^2 + 3^x$
Write $3^x = (6^x)^{\log_6 3}$, but this is complicated.
Instead, try to express numerator and denominator in terms of $3^x$ and $2^x$:
Numerator: $12^x + 1 = (2^2 \cdot 3)^x + 1 = 2^{2x} 3^x + 1$
Denominator: $6^{2x} + 3^x = (2 \cdot 3)^{2x} + 3^x = 2^{2x} 3^{2x} + 3^x$
Factor $3^x$ from denominator:
$3^x (2^{2x} 3^x + 1)$
So expression is:
$$\frac{2^{2x} 3^x + 1}{3^x (2^{2x} 3^x + 1)}$$
Cancel common factor $2^{2x} 3^x + 1$:
$$\frac{\cancel{2^{2x} 3^x + 1}}{3^x \cancel{2^{2x} 3^x + 1}} = \frac{1}{3^x}$$
5. **Final answers:**
a) $\boxed{\frac{3^n}{2}}$
b) $\boxed{\frac{1}{3^x}}$
Simplify Expressions 623Eb5
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