Answer :
## Question 24: Solve [tex]\( 3^{x-7} \times 3^x = 27 \)[/tex]
### Step-by-Step Solution:
1. Combine the exponential expressions:
[tex]\[ 3^{x-7} \times 3^x = 27 \][/tex]
Using the property of exponents [tex]\(a^m \times a^n = a^{m+n}\)[/tex], we combine the exponents:
[tex]\[ 3^{(x-7) + x} = 27 \][/tex]
Simplify the exponent:
[tex]\[ 3^{2x-7} = 27 \][/tex]
2. Rewrite 27 as a power of 3:
We know that [tex]\(27 = 3^3\)[/tex], thus:
[tex]\[ 3^{2x-7} = 3^3 \][/tex]
3. Equate the exponents:
Since the bases are the same and the equation [tex]\(a^m = a^n\)[/tex] implies [tex]\(m=n\)[/tex], we equate the exponents:
[tex]\[ 2x - 7 = 3 \][/tex]
4. Solve for [tex]\(x\)[/tex]:
Solve the linear equation for [tex]\(x\)[/tex]:
\begin{align}
2x - 7 &= 3 \\
2x &= 3 + 7 \\
2x &= 10 \\
x &= \frac{10}{2} \\
x &= 5
\end{align}
Thus, the truth set of [tex]\( 3^{x-7} \times 3^x = 27 \)[/tex] is [tex]\( \boxed{5} \)[/tex].
Let's verify the intermediate steps:
- The left-hand side simplification is [tex]\(2x - 7\)[/tex],
- We identified [tex]\(27\)[/tex] as [tex]\(3^3\)[/tex],
- This led to the equation [tex]\(2x - 7 = 3\)[/tex], and solving for [tex]\(x\)[/tex] yielded [tex]\(x = 5\)[/tex].
Given these verified intermediate results, [tex]\(x = 5\)[/tex] is indeed the correct solution.
So, [tex]\( c) 5 \)[/tex] is the correct answer.
### Step-by-Step Solution:
1. Combine the exponential expressions:
[tex]\[ 3^{x-7} \times 3^x = 27 \][/tex]
Using the property of exponents [tex]\(a^m \times a^n = a^{m+n}\)[/tex], we combine the exponents:
[tex]\[ 3^{(x-7) + x} = 27 \][/tex]
Simplify the exponent:
[tex]\[ 3^{2x-7} = 27 \][/tex]
2. Rewrite 27 as a power of 3:
We know that [tex]\(27 = 3^3\)[/tex], thus:
[tex]\[ 3^{2x-7} = 3^3 \][/tex]
3. Equate the exponents:
Since the bases are the same and the equation [tex]\(a^m = a^n\)[/tex] implies [tex]\(m=n\)[/tex], we equate the exponents:
[tex]\[ 2x - 7 = 3 \][/tex]
4. Solve for [tex]\(x\)[/tex]:
Solve the linear equation for [tex]\(x\)[/tex]:
\begin{align}
2x - 7 &= 3 \\
2x &= 3 + 7 \\
2x &= 10 \\
x &= \frac{10}{2} \\
x &= 5
\end{align}
Thus, the truth set of [tex]\( 3^{x-7} \times 3^x = 27 \)[/tex] is [tex]\( \boxed{5} \)[/tex].
Let's verify the intermediate steps:
- The left-hand side simplification is [tex]\(2x - 7\)[/tex],
- We identified [tex]\(27\)[/tex] as [tex]\(3^3\)[/tex],
- This led to the equation [tex]\(2x - 7 = 3\)[/tex], and solving for [tex]\(x\)[/tex] yielded [tex]\(x = 5\)[/tex].
Given these verified intermediate results, [tex]\(x = 5\)[/tex] is indeed the correct solution.
So, [tex]\( c) 5 \)[/tex] is the correct answer.