Solve x - Square Root of x = Square Root of x: Finding All Values

Radical Equations with Square Root Isolation

xx=x x-\sqrt{x}=\sqrt{x}

What are the possible values of X?

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Step-by-step video solution

Watch the teacher solve the problem with clear explanations
00:00 Find the X values that satisfy the equation
00:03 Collect terms
00:20 Break down X into X squared root
00:26 Find the common factor, and take out of parentheses
00:38 The right side of the equation is 0 because of the subtraction we did
00:42 Find what makes each factor equal zero in the multiplication
00:52 Solve the first option first, square it
00:57 This is one solution
01:01 Now let's solve the second option, isolate X
01:05 Square it to find the solution
01:10 And this is the second possible solution
01:13 And this is the solution to the problem

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

xx=x x-\sqrt{x}=\sqrt{x}

What are the possible values of X?

2

Step-by-step solution

Let's solve the equation xx=x x - \sqrt{x} = \sqrt{x} .

Step 1: Start by simplifying the equation.
The equation is given by:

xx=x x - \sqrt{x} = \sqrt{x}

Step 2: Isolate the square root by adding x\sqrt{x} to both sides:

x=2x x = 2\sqrt{x}

Step 3: Square both sides to eliminate the square root.

(x)2=(2x)2 (x)^2 = (2\sqrt{x})^2

This simplifies to:

x2=4x x^2 = 4x

Step 4: Simplify and solve the quadratic equation:

Move all terms to one side:

x24x=0 x^2 - 4x = 0

Step 5: Factor the quadratic equation:

x(x4)=0 x(x - 4) = 0

Step 6: Solve for x x to find potential solutions:

x=0 x = 0 or x=4 x = 4 .

Step 7: Check solutions by substituting back into the original equation:

  • For x=0 x = 0 :
  • 00=0 0 - \sqrt{0} = \sqrt{0} which simplifies to 0=0 0 = 0 . True.

  • For x=4 x = 4 :
  • 44=4 4 - \sqrt{4} = \sqrt{4} which simplifies to 42=2 4 - 2 = 2 . True.

Therefore, both solutions are valid.

The possible values of x x are 0 and 4.

Therefore, the solution to the problem is 0,4 0, 4 . Thus, the correct choice is option 2.

3

Final Answer

0, 4

Key Points to Remember

Essential concepts to master this topic
  • Domain: Square roots require non-negative values under radical
  • Technique: Isolate x \sqrt{x} to get x=2x x = 2\sqrt{x} , then square both sides
  • Check: Substitute x = 0 and x = 4: both give 0 = 0 and 2 = 2 ✓

Common Mistakes

Avoid these frequent errors
  • Forgetting to check solutions after squaring
    Don't assume all solutions from x2=4x x^2 = 4x are valid = potential extraneous solutions! Squaring both sides can introduce false solutions that don't work in the original equation. Always substitute each solution back into xx=x x - \sqrt{x} = \sqrt{x} to verify.

Practice Quiz

Test your knowledge with interactive questions

\( (4b-3)(4b-3) \)

Rewrite the above expression as an exponential summation expression:

FAQ

Everything you need to know about this question

Why do I need to isolate the square root first?

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Isolating x \sqrt{x} gives you one clean radical on each side. This makes squaring both sides much simpler and avoids messy algebra with multiple square root terms.

What happens if I square both sides without isolating first?

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You'd get (xx)2=(x)2 (x - \sqrt{x})^2 = (\sqrt{x})^2 , which expands to x22xx+x=x x^2 - 2x\sqrt{x} + x = x . Now you still have a square root term to deal with!

Why can't x be negative in this problem?

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The expression x \sqrt{x} requires x ≥ 0 for real numbers. Negative values under a square root aren't defined in basic algebra, so we only consider non-negative solutions.

How do I know both solutions are actually correct?

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Always substitute back into the original equation:

  • For x = 0: 00=0 0 - \sqrt{0} = \sqrt{0} becomes 0 = 0 ✓
  • For x = 4: 44=4 4 - \sqrt{4} = \sqrt{4} becomes 2 = 2 ✓

Could there be other methods to solve this equation?

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You could also substitute u=x u = \sqrt{x} to get u2u=u u^2 - u = u , then solve u2=2u u^2 = 2u . This gives the same result but with different variable names!

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