Solve for X: x^5/16 = 2 Fifth-Power Equation

Fifth Root Equations with Fraction Isolation

Solve the following problem:

x516=2 \frac{x^5}{16}=2

❤️ 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
00:00 Find X
00:03 Isolate X
00:12 Extract a fifth root
00:22 Break down 32 into 2 to the power of 5
00:25 A fifth root cancels out a power of 5
00:28 And this is the solution to the question

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

Solve the following problem:

x516=2 \frac{x^5}{16}=2

2

Step-by-step solution

Let's solve the given equation:

x516=2 \frac{x^5}{16}=2

Begin by eliminating the denominator on the left side of the given equation, we can achieve this by multiplying both sides of the equation by the common denominator - which is the number 16:

x516=2/16x5=216x5=32 \frac{x^5}{16}=2 \hspace{8pt}\text{/}\cdot 16\\ x^5=2\cdot 16\\ x^5=32

From here, proceed to perform on both sides the opposite operation to the fifth power that applies to the unknown in the equation, which is the fifth root operation, using the laws of exponents:

a. Definition of root as a power:

an=a1n \sqrt[n]{a}=a^{\frac{1}{n}} and two laws of exponents:

b. Law of exponents for power of a power:

(am)n=amn (a^m)^n=a^{m\cdot n}

Let's continue solving the equation:
x5=32/5x55=325(x5)15=2x515=2x=2 x^5=32 \hspace{8pt}\text{/}\sqrt[5]{\hspace{6pt}}\\ \sqrt[5]{ x^5}=\sqrt[5]{ 32}\\ (x^5)^{\frac{1}{5}}=2\\ x^{5\cdot\frac{1}{5}}=2\\ \boxed{x=2}

In the first stage, we applied the fifth root to both sides of the equation. Applying the definition of root as a power (a.) on the left side. In the next stage - we applied the law of exponents for a power of a power (b.) on the left side. Remember that raising a number to the power of 1 doesn't change the number.

Additionally, an odd-order power preserves the sign of the number it's applied to, taking an odd-order root requires consideration of only one case regarding the sign of the number being rooted (this is unlike taking an even-order root, which requires consideration of two possible cases - positive and negative),

Let's summarize the solution of the equation:

x516=2/16x5=32/5x=2 \frac{x^5}{16}=2 \hspace{8pt}\text{/}\cdot 16\\ x^5=32 \hspace{8pt}\text{/}\sqrt[5]{\hspace{6pt}}\\ \boxed{x=2}

Therefore, the correct answer is answer B.

3

Final Answer

x=2 x=2

Key Points to Remember

Essential concepts to master this topic
  • Rule: Multiply both sides by denominator to isolate the power term
  • Technique: Apply fifth root: x55=325 \sqrt[5]{x^5} = \sqrt[5]{32} gives x = 2
  • Check: Substitute back: 2516=3216=2 \frac{2^5}{16} = \frac{32}{16} = 2

Common Mistakes

Avoid these frequent errors
  • Trying to take the fifth root without clearing the fraction first
    Don't try to take x5165 \sqrt[5]{\frac{x^5}{16}} directly = complicated root of fraction! This makes the problem much harder and leads to errors. Always multiply both sides by 16 first to get x5=32 x^5 = 32 , then take the fifth root.

Practice Quiz

Test your knowledge with interactive questions

Determine if the simplification shown below is correct:

\( \frac{7}{7\cdot8}=8 \)

FAQ

Everything you need to know about this question

Why do I multiply by 16 instead of dividing by it?

+

Multiplying by 16 eliminates the fraction completely! If you divide by 16, you'd get x5256=18 \frac{x^5}{256} = \frac{1}{8} , which is even more complicated.

How do I know that the fifth root of 32 is 2?

+

Think: what number raised to the 5th power equals 32? Since 25=2×2×2×2×2=32 2^5 = 2 \times 2 \times 2 \times 2 \times 2 = 32 , we know 325=2 \sqrt[5]{32} = 2 .

Why don't I need to consider negative solutions like with square roots?

+

Odd roots are different from even roots! Since 5 is odd, there's only one real fifth root. Unlike square roots, we don't get both positive and negative answers.

What if I can't figure out the fifth root easily?

+

Try small integers first! Check if 25 2^5 , 35 3^5 , etc. equal your number. For this problem, 25=32 2^5 = 32 works perfectly.

Can I use a calculator for fifth roots?

+

Yes! Use the power function: 321/5=320.2=2 32^{1/5} = 32^{0.2} = 2 . But learning to recognize perfect fifth powers like 25=32 2^5 = 32 helps you solve faster.

🌟 Unlock Your Math Potential

Get unlimited access to all 18 Factorization 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