Solve 7⁴ × 8³ × (1/7)⁴: Power and Reciprocal Multiplication

Power Rules with Reciprocal Simplification

7483(17)4=? 7^4\cdot8^3\cdot(\frac{1}{7})^4=\text{?}

❤️ Continue Your Math Journey!

We have hundreds of course questions with personalized recommendations + Account 100% premium

Step-by-step video solution

Watch the teacher solve the problem with clear explanations
00:09 Let's simplify the problem together.
00:15 If a fraction has an exponent, both the top and bottom numbers are raised to that power.
00:24 We'll use this rule for our exercise, so let's get started!
00:30 Now, let's reduce wherever we can.
00:38 Remember, one raised to any power is always one.
00:44 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

7483(17)4=? 7^4\cdot8^3\cdot(\frac{1}{7})^4=\text{?}

2

Step-by-step solution

We use the formula:

(ab)n=anbn (\frac{a}{b})^n=\frac{a^n}{b^n}

We decompose the fraction inside of the parentheses:

(17)4=1474 (\frac{1}{7})^4=\frac{1^4}{7^4}

We obtain:

74×83×1474 7^4\times8^3\times\frac{1^4}{7^4}

We simplify the powers: 74 7^4

We obtain:

83×14 8^3\times1^4

Remember that the number 1 in any power is equal to 1, thus we obtain:

83×1=83 8^3\times1=8^3

3

Final Answer

83 8^3

Key Points to Remember

Essential concepts to master this topic
  • Rule: (1a)n=1an (\frac{1}{a})^n = \frac{1}{a^n} converts reciprocals to fraction form
  • Technique: Cancel 74 7^4 with 174 \frac{1}{7^4} leaving only 83 8^3
  • Check: Verify 74×174=1 7^4 \times \frac{1}{7^4} = 1 and 1×83=512 1 \times 8^3 = 512

Common Mistakes

Avoid these frequent errors
  • Adding exponents instead of recognizing cancellation
    Don't add 4 + 3 + 4 = 11 thinking the answer is some power with exponent 11! This ignores that 74 7^4 and (17)4=174 (\frac{1}{7})^4 = \frac{1}{7^4} are reciprocals that multiply to 1. Always look for bases that can cancel first.

Practice Quiz

Test your knowledge with interactive questions

Which of the following is equivalent to \( 100^0 \)?

FAQ

Everything you need to know about this question

Why does 74×(17)4 7^4 \times (\frac{1}{7})^4 equal 1?

+

Because (17)4=174 (\frac{1}{7})^4 = \frac{1}{7^4} , so you get 74×174=7474=1 7^4 \times \frac{1}{7^4} = \frac{7^4}{7^4} = 1 . Any number divided by itself equals 1!

Can I calculate 74 7^4 and 83 8^3 separately first?

+

You could, but it's unnecessary work! 74=2401 7^4 = 2401 and 83=512 8^3 = 512 , but since 74 7^4 cancels with 174 \frac{1}{7^4} , you just need 83=512 8^3 = 512 .

What if the bases were different, like 74×83×(16)4 7^4 \times 8^3 \times (\frac{1}{6})^4 ?

+

Then nothing would cancel! You'd need to calculate each part separately: 74×83×164 7^4 \times 8^3 \times \frac{1}{6^4} . Cancellation only works when bases are the same.

How do I know when to look for cancellation?

+

Always scan for matching bases with reciprocal relationships! If you see an a^n and (1a)n (\frac{1}{a})^n or 1an \frac{1}{a^n} , they will cancel to 1.

Why is 14 1^4 important in the solution?

+

Because (17)4=1474 (\frac{1}{7})^4 = \frac{1^4}{7^4} , and any power of 1 equals 1. This helps show that after cancellation, we're left with 83×1=83 8^3 \times 1 = 8^3 .

🌟 Unlock Your Math Potential

Get unlimited access to all 18 Exponents Rules questions, detailed video solutions, and personalized progress tracking.

📹

Unlimited Video Solutions

Step-by-step explanations for every problem

📊

Progress Analytics

Track your mastery across all topics

🚫

Ad-Free Learning

Focus on math without distractions

No credit card required • Cancel anytime

More Questions

Click on any question to see the complete solution with step-by-step explanations