Examples with solutions for Power of a Power: Presenting powers with negative exponents as fractions

Exercise #1

Insert the corresponding expression:

((5×3)4)3= \left(\left(5\times3\right)^4\right)^{-3}=

Video Solution

Step-by-Step Solution

To solve the problem, let us simplify the expression ((5×3)4)3\left(\left(5\times3\right)^4\right)^{-3}.

First, recognize that the expression inside the parentheses, 5×35 \times 3, can be multiplied to give us 15. However, we'll focus on exponent rules directly.

  • Step 1: Apply the Power of a Power Rule.
    Using the formula (am)n=am×n(a^m)^n = a^{m \times n}, simplification gives: ((5×3)4)3=((5×3)4×3)=(5×3)12.\left(\left(5\times3\right)^4\right)^{-3} = \left( (5 \times 3)^{4 \times -3} \right) = \left(5\times3\right)^{-12}.
  • Step 2: Apply the Negative Exponent Rule.
    Using an=1ana^{-n} = \frac{1}{a^n}, the expression becomes: (5×3)12=1(5×3)12.\left(5\times3\right)^{-12} = \frac{1}{\left(5\times3\right)^{12}}.

Therefore, the solution to the given expression is 1(5×3)12\frac{1}{\left(5\times3\right)^{12}}.

Now, let's verify the answer with the choices provided:

  • Choice 1: 1(5×3)12\frac{1}{\left(5\times3\right)^{12}} - This matches our solution.
  • Choice 2: (5×3)12(5\times3)^{12} - Incorrect, doesn't account for the negative exponent.
  • Choice 3: 1(5×3)1\frac{1}{\left(5\times3\right)^{-1}} - Incorrect power and doesn't represent the full expression.
  • Choice 4: 1(5×3)1\frac{1}{\left(5\times3\right)^1} - Incorrect power and doesn't reflect the original problem.

Thus, the correct choice is Choice 1: 1(5×3)12\frac{1}{\left(5\times3\right)^{12}}.

Answer

1(5×3)12 \frac{1}{\left(5\times3\right)^{12}}

Exercise #2

Insert the corresponding expression:

((7×6)5)3= \left(\left(7\times6\right)^{-5}\right)^3=

Video Solution

Step-by-Step Solution

To solve this problem, we must simplify the expression ((7×6)5)3\left(\left(7 \times 6\right)^{-5}\right)^3.

We'll follow these steps:

  • Step 1: Apply the power of a power rule.
  • Step 2: Simplify the expression into a single exponent.
  • Step 3: Convert the negative exponent to a fraction form.

Now, let's work through each step:

Step 1: The expression (7×6)5\left(7 \times 6\right)^{-5} is raised to the power 3. By the power of a power rule, we multiply the exponents:

((7×6)5)3=(7×6)5×3=(7×6)15 \left((7 \times 6)^{-5}\right)^3 = (7 \times 6)^{-5 \times 3} = (7 \times 6)^{-15}

Step 2: This simplifies the expression to (7×6)15(7 \times 6)^{-15}.

Step 3: Since we have a negative exponent, we convert it to a fraction:

(7×6)15=1(7×6)15 (7 \times 6)^{-15} = \frac{1}{(7 \times 6)^{15}}

Therefore, the simplified expression is:

1(7×6)15 \frac{1}{\left(7 \times 6\right)^{15}}

Comparing this result with the given choices, the correct answer is:

- Choice 3: 1(7×6)15 \frac{1}{\left(7 \times 6\right)^{15}}

The other choices are incorrect because they either have the wrong exponent or incorrectly handle the negative exponent.

Thus, the correct answer to the problem is 1(7×6)15 \frac{1}{\left(7 \times 6\right)^{15}} .

Answer

1(7×6)15 \frac{1}{\left(7\times6\right)^{15}}

Exercise #3

Insert the corresponding expression:

((8×4)7)6= \left(\left(8\times4\right)^{-7}\right)^6=

Video Solution

Step-by-Step Solution

To solve this expression, we will follow these steps using the rules of exponents:

  • Step 1: Apply the power of a power rule.
  • Step 2: Use the negative exponent rule to express the result as a fraction.

Now, let's apply each step:

Step 1: Apply the power of a power rule
Given: ((8×4)7)6\left(\left(8\times4\right)^{-7}\right)^6.
According to the power of a power rule, (am)n=amn(a^m)^n = a^{m \cdot n}.
So, ((8×4)7)6=(8×4)7×6=(8×4)42\left(\left(8\times4\right)^{-7}\right)^6 = \left(8\times4\right)^{-7 \times 6} = \left(8\times4\right)^{-42}.

Step 2: Use the negative exponent rule
Now, apply the negative exponent rule: am=1ama^{-m} = \frac{1}{a^m}.
Thus, (8×4)42=1(8×4)42\left(8\times4\right)^{-42} = \frac{1}{\left(8\times4\right)^{42}}.

The simplified expression is 1(8×4)42\frac{1}{\left(8\times4\right)^{42}}.

Now, let's determine which of the provided answer choices is correct:
- Choice 1: 1(8×4)42\frac{1}{\left(8\times4\right)^{-42}} is incorrect because the exponent should not be negative.
- Choice 2: 1(8×4)42\frac{1}{\left(8\times4\right)^{42}} is correct as it matches our solution.
- Choice 3: 1(8×4)1\frac{1}{\left(8\times4\right)^{-1}} is incorrect because it does not match our calculated exponent.
- Choice 4: 1(8×4)1\frac{1}{\left(8\times4\right)^1} is incorrect as the exponent is too small.

Therefore, the correct answer is 1(8×4)42\frac{1}{\left(8\times4\right)^{42}}, which corresponds to Choice 2.

Answer

1(8×4)42 \frac{1}{\left(8\times4\right)^{42}}

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