1. **Problem Statement:** Solve the exponential equation and convert it into an algebraic expression.
2. **General Formula:** Exponential equations often have the form $a^{f(x)} = b$, where $a$ and $b$ are constants and $f(x)$ is an algebraic expression.
3. **Important Rules:**
- If $a^{m} = a^{n}$, then $m = n$ (provided $a > 0$ and $a \neq 1$).
- Use logarithms to solve equations when bases differ.
4. **Example 1:** Solve $2^{x+1} = 8$
- Express 8 as a power of 2: $8 = 2^3$
- So, $2^{x+1} = 2^3$
- By the rule, $x + 1 = 3$
- Solve for $x$: $x = 3 - 1 = 2$
5. **Example 2:** Solve $3^{2x} = 81$
- Express 81 as a power of 3: $81 = 3^4$
- So, $3^{2x} = 3^4$
- Equate exponents: $2x = 4$
- Solve for $x$: $x = 2$
6. **Example 3:** Solve $5^{x} = 20$
- Since 20 is not a power of 5, take logarithm on both sides:
$$x = \frac{\log(20)}{\log(5)}$$
- This is the algebraic expression for $x$.
7. **Summary:** Exponential equations can be converted to algebraic expressions by rewriting terms with the same base or using logarithms when bases differ. This allows solving for the variable in the exponent.
**Final answers:**
- Example 1: $x=2$
- Example 2: $x=2$
- Example 3: $x=\frac{\log(20)}{\log(5)}$
Exponential Algebra 4Cc2C4
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