Solve (4²/7⁴)²: Calculating Powers of Complex Fractions

Power Rules with Compound Exponents

(4274)2= (\frac{4^2}{7^4})^2=

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Step-by-step video solution

Watch the teacher solve the problem with clear explanations
00:08 Let's simplify.
00:11 We will use a special formula for fraction exponents.
00:15 When a fraction is raised to a power, we need to raise both the top and bottom to that power.
00:22 We'll use this formula in our exercise.
00:26 Next, let's apply the power of a power rule.
00:29 If we have a number A raised to the power of N, then to the power of M,
00:35 we write it as A to the power of the product of exponents, M times N.
00:41 We'll use this rule in our exercise as well.
00:45 Now, let's multiply the exponents and see what we get.
00:49 And that's how we find the solution to our question!

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

(4274)2= (\frac{4^2}{7^4})^2=

2

Step-by-step solution

(4274)2=42×274×2=4478 (\frac{4^2}{7^4})^2=\frac{4^{2\times2}}{7^{4\times2}}=\frac{4^4}{7^8}

3

Final Answer

4478 \frac{4^4}{7^8}

Key Points to Remember

Essential concepts to master this topic
  • Power Rule: When raising a power to a power, multiply the exponents
  • Technique: Apply power rule to numerator and denominator separately: (42)2=44 (4^2)^2 = 4^4 and (74)2=78 (7^4)^2 = 7^8
  • Check: Verify by calculating step by step: 42=16 4^2 = 16 , then 162=256 16^2 = 256 matches 44 4^4

Common Mistakes

Avoid these frequent errors
  • Adding exponents instead of multiplying when raising a power to a power
    Don't add the exponents like (42)2=42+2=44 (4^2)^2 = 4^{2+2} = 4^4 for the numerator but (74)2=74+2=76 (7^4)^2 = 7^{4+2} = 7^6 for the denominator = inconsistent application and wrong answer! The power rule requires multiplying exponents, not adding them. Always multiply: (am)n=am×n (a^m)^n = a^{m \times n} .

Practice Quiz

Test your knowledge with interactive questions

\( 112^0=\text{?} \)

FAQ

Everything you need to know about this question

Why do I multiply the exponents instead of adding them?

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When you raise a power to another power, you're essentially multiplying the base by itself multiple times. For example, (42)2 (4^2)^2 means 42×42 4^2 \times 4^2 , which by the multiplication rule becomes 42+2=44 4^{2+2} = 4^4 . The power rule (am)n=am×n (a^m)^n = a^{m \times n} is a shortcut for this process!

Do I apply the outer exponent to both the numerator and denominator?

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Yes! When you have (ab)n (\frac{a}{b})^n , the exponent applies to the entire fraction. This means (4274)2=(42)2(74)2 (\frac{4^2}{7^4})^2 = \frac{(4^2)^2}{(7^4)^2} . Apply the power rule to both the top and bottom separately.

What's the difference between 42×2 4^2 \times 2 and (42)2 (4^2)^2 ?

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42×2=16×2=32 4^2 \times 2 = 16 \times 2 = 32 , but (42)2=44=256 (4^2)^2 = 4^4 = 256 . The parentheses make all the difference! Without parentheses, you multiply the result by 2. With parentheses, you raise the entire power to the 2nd power.

Can I simplify this fraction further?

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The final answer 4478 \frac{4^4}{7^8} cannot be simplified further because 4 and 7 share no common factors. However, you could write it as 2565764801 \frac{256}{5764801} if you calculate the actual values, but the exponential form is preferred.

How can I check my work without a calculator?

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Work backwards! Start with 4274=162401 \frac{4^2}{7^4} = \frac{16}{2401} , then square this fraction: (162401)2=16224012=2565764801 (\frac{16}{2401})^2 = \frac{16^2}{2401^2} = \frac{256}{5764801} . This should equal 4478=2565764801 \frac{4^4}{7^8} = \frac{256}{5764801}

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