Evaluate (6×8)/(2×7) Raised to the Power of -5: Complex Fraction Exercise

Negative Exponents with Complex Fractions

Insert the corresponding expression:

(6×82×7)5= \left(\frac{6\times8}{2\times7}\right)^{-5}=

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Step-by-step video solution

Watch the teacher solve the problem with clear explanations
00:09 Let's simplify this problem together.
00:13 When a fraction is raised to a negative exponent, like negative N, just flip the fraction and use positive N.
00:19 So, it's the reciprocal fraction raised to the positive exponent N.
00:24 Alright, let's use this rule in our exercise.
00:28 We'll change to the reciprocal and raise it to the positive exponent.
00:32 And there you go! That's the solution.

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

Insert the corresponding expression:

(6×82×7)5= \left(\frac{6\times8}{2\times7}\right)^{-5}=

2

Step-by-step solution

To solve the problem, we need to find the equivalent expression for the given negative exponent:

Step 1: Identify the base fraction as 6×82×7 \frac{6\times8}{2\times7} .

Step 2: Apply the negative exponent rule:

The expression (6×82×7)5 \left(\frac{6\times8}{2\times7}\right)^{-5} can be rewritten using the property that (ab)n=(ba)n \left(\frac{a}{b}\right)^{-n} = \left(\frac{b}{a}\right)^n .

Thus, we have:

(6×82×7)5=(2×76×8)5 \left(\frac{6\times8}{2\times7}\right)^{-5} = \left(\frac{2\times7}{6\times8}\right)^5

Therefore, the correct equivalent expression is:

(2×76×8)5 \left(\frac{2\times7}{6\times8}\right)^5

Hence, the choice corresponding to this expression is correct.

Therefore, the solution to the problem is (2×76×8)5 \left(\frac{2\times7}{6\times8}\right)^5 , which corresponds to choice 1.

3

Final Answer

(2×76×8)5 \left(\frac{2\times7}{6\times8}\right)^5

Key Points to Remember

Essential concepts to master this topic
  • Rule: Negative exponent flips the fraction and makes exponent positive
  • Technique: (ab)n=(ba)n \left(\frac{a}{b}\right)^{-n} = \left(\frac{b}{a}\right)^n switches numerator and denominator
  • Check: Verify by converting back: (2×76×8)5 \left(\frac{2×7}{6×8}\right)^5 raised to -1/5 gives original ✓

Common Mistakes

Avoid these frequent errors
  • Making the exponent negative without flipping the fraction
    Don't write (6×82×7)5 -\left(\frac{6×8}{2×7}\right)^5 = wrong negative result! The negative exponent rule doesn't add a negative sign to the front. Always flip the fraction first, then make the exponent positive.

Practice Quiz

Test your knowledge with interactive questions

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

FAQ

Everything you need to know about this question

Why does a negative exponent flip the fraction?

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A negative exponent means "take the reciprocal". Since an=1an a^{-n} = \frac{1}{a^n} , when you have (6×82×7)5 \left(\frac{6×8}{2×7}\right)^{-5} , it becomes 1(6×82×7)5 \frac{1}{\left(\frac{6×8}{2×7}\right)^5} , which simplifies to the flipped fraction with positive exponent.

Do I need to calculate the actual numbers first?

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No! You can apply the negative exponent rule directly to the fraction form. Converting (6×82×7)5 \left(\frac{6×8}{2×7}\right)^{-5} to (2×76×8)5 \left(\frac{2×7}{6×8}\right)^5 is correct without calculating 48/14 first.

Does the negative exponent make the whole answer negative?

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No! A negative exponent only affects the position of terms (flipping fractions), not the sign of the final result. The answer (2×76×8)5 \left(\frac{2×7}{6×8}\right)^5 is still positive.

What if I see a negative sign in front of the parentheses?

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Be careful to distinguish between a negative exponent and a negative coefficient. In this problem, the -5 is an exponent, not a negative sign multiplying the entire expression.

How can I remember the negative exponent rule?

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Think: "Negative exponent = flip and make positive". Just like 23=123 2^{-3} = \frac{1}{2^3} , fractions with negative exponents flip: (ab)n=(ba)n \left(\frac{a}{b}\right)^{-n} = \left(\frac{b}{a}\right)^n .

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