Solve the Nested Radical Equation: √(16/∛64) = √(x²)

Radical Equations with Nested Operations

Solve the following exercise:

16643=x2 \sqrt{\frac{16}{\sqrt[3]{64}}}=\sqrt{x^2}

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Step-by-step video solution

Watch the teacher solve the problem with clear explanations
00:00 Solve the following problem
00:03 Square it in order to eliminate the root
00:29 Break down 64 into 4 cubed
00:35 A cube root cancels out a cube power
00:46 This is the solution

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

Solve the following exercise:

16643=x2 \sqrt{\frac{16}{\sqrt[3]{64}}}=\sqrt{x^2}

2

Step-by-step solution

To solve the problem 16643=x2 \sqrt{\frac{16}{\sqrt[3]{64}}} = \sqrt{x^2} , we proceed step-by-step as follows:

  • First, we simplify 643 \sqrt[3]{64} . Since 64=43 64 = 4^3 , it follows that 643=4 \sqrt[3]{64} = 4 .
  • Next, simplify the expression 16643 \frac{16}{\sqrt[3]{64}} :
    164=4\frac{16}{4} = 4.
  • Now, take the square root of this simplified value. Thus, 4=2 \sqrt{4} = 2 .
  • The equation simplifies to: x2=2 \sqrt{x^2} = 2 . Since x2=x\sqrt{x^2} = |x|, we have x=2|x| = 2.
  • This implies x=2 x = 2 or x=2 x = -2 .
  • However, choices include only positive solutions, and thus x=2 x = 2 .

Therefore, the solution to the problem is x=2 x = 2 .

3

Final Answer

x=2 x=2

Key Points to Remember

Essential concepts to master this topic
  • Order: Simplify innermost expressions first, then work outward
  • Technique: Calculate 643=4 \sqrt[3]{64} = 4 , then 164=4 \frac{16}{4} = 4
  • Check: Substitute x = 2: 22=4=2 \sqrt{2^2} = \sqrt{4} = 2

Common Mistakes

Avoid these frequent errors
  • Ignoring absolute value in square root of x²
    Don't assume x2=x \sqrt{x^2} = x = positive x only! This misses negative solutions. x2=x \sqrt{x^2} = |x| means both x = 2 and x = -2 are valid. Always remember that square roots of squared variables give absolute values.

Practice Quiz

Test your knowledge with interactive questions

Solve the following exercise:

\( \sqrt{\frac{2}{4}}= \)

FAQ

Everything you need to know about this question

Why does the cube root of 64 equal 4?

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Because 4 × 4 × 4 = 64! The cube root asks: what number multiplied by itself three times gives 64? Since 43=64 4^3 = 64 , we have 643=4 \sqrt[3]{64} = 4 .

What's the difference between √(x²) and just x?

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x2=x \sqrt{x^2} = |x| (absolute value), not just x! This means if x = -2, then (2)2=4=2 \sqrt{(-2)^2} = \sqrt{4} = 2 , which is positive. The square root always gives a non-negative result.

Should I work from inside out or outside in?

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Always work inside out! Start with the innermost operation (cube root), then move to the next layer (division), then the outermost (square root). This follows the natural order of operations.

Why isn't x = -2 listed as an answer choice?

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Many textbooks focus on principal solutions or positive values when dealing with basic radical equations. Both x = 2 and x = -2 satisfy x=2 |x| = 2 , but the question likely expects the positive solution.

How do I simplify nested radicals like this?

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Break it into steps: 1) Simplify innermost radical first, 2) Perform any arithmetic operations, 3) Simplify the outer radical. Don't try to do everything at once!

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