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If \(2 \sqrt{x}=x-3\), which of the following is the solution set for \(x\) ? A) \(\\{-1,9\\}\) B) \(\\{1,-9\\}\) C) \(\\{9\\}\) D) \(\\{1,9\\}\)

Short Answer

Expert verified
The correct solution set for the given equation is C) \(\{9\}\).

Step by step solution

01

Square both sides of the equation

To eliminate the square root, square both sides of the equation \(2 \sqrt{x}=x-3\). This will give the equation: \[(2\sqrt{x})^2 = (x-3)^2.\]
02

Simplify the equation

Simplify both sides of the equation from the previous step. On the left side, the square and the square root will cancel out: \[(2\sqrt{x})^2 = 4x,\] while on the right side, expand the binomial: \[(x-3)^2 = x^2 - 6x + 9.\] This results in the equation: \[4x = x^2 - 6x + 9.\]
03

Rearrange and Solve the Quadratic Equation

To solve for x, move all terms to one side of the equation, creating a quadratic equation: \[x^2 - 10x + 9 = 0.\] Now, attempt to factor this quadratic equation: \[(x - 1)(x - 9)= 0\] The solutions for x are 1 and 9: \[x=1, x=9.\]
04

Verify the solutions

To verify whether the solutions are valid, plug each solution back into the original equation: For x = 1: \(2 \sqrt{1}=1-3\) gives \(2 \neq -2\). In this case, \(x=1\) is not a valid solution. For x = 9: \(2 \sqrt{9}=9-3\) gives \(6=6\). In this case, \(x=9\) is a valid solution. So, the correct solution set for the given equation is \(\{9\}\). The correct answer is: C) \(\{9\}\).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Quadratic Equations
Quadratic equations are a cornerstone in algebra and are typically expressed in the standard form of \(ax^2 + bx + c = 0\). These equations are called 'quadratic' because the highest power of the variable \(x\) is 2. Solving quadratic equations involves finding the value(s) of \(x\) that make the equation true. There are several methods to solve quadratic equations, such as factoring, using the quadratic formula, or completing the square. Each method has its own application based on the equation's characteristics, such as discerning the presence of integer solutions or dealing with complex numbers in more advanced cases.
Algebraic Solutions
When solving algebraic equations such as the one given, we often employ a series of transformations to simplify or reframe the problem. These transformations can include expanding expressions, combining like terms, and moving terms across the equality to isolate variables. In the case of the equation \(2 \sqrt{x}=x-3\), we initially squared both sides to eliminate the square root, leading to a simplified algebraic form: \(4x = x^2 - 6x + 9\). This crucial step transforms the problem into a quadratic equation, which can then be managed using standard techniques like factoring. Simplification helps transition complex or less intuitive equations into forms that are easier to handle and proceed with.
Problem Solving
Effective problem-solving involves a clear understanding of the problem and a structured approach to finding a solution. For quadratic equations, this typically means:
  • Identifying the type of equation and selecting the appropriate solving method (factoring, quadratic formula, etc.).
  • Applying algebraic techniques to manipulate the equation into a solvable form.
  • Considering all potential solutions and understanding how each step influences the entire equation.
In this problem, after identifying and factoring the quadratic equation \(x^2 - 10x + 9 = 0\), we found potential solutions at \(x=1\) and \(x=9\). Recognizing which parts of the quadratic are influenced by changes to variables aids significantly in managing such problems.
Validating Solutions
Validation is a critical step in solving equations which ensures that the solutions obtained satisfy the original equation. Sometimes transforming an equation might introduce extraneous solutions that don't satisfy the condition given by the problem. After solving \(x=1\) and \(x=9\) from the quadratic equation, we put these values back into the original equation \(2 \sqrt{x}=x-3\) to verify. For this exercise:
  • At \(x=1\), the transformation fails as it yields \(2 eq -2\), indicating it's not a valid solution.
  • At \(x=9\), the validation confirms correctness with both sides equating to 6.
This real-world contextual check emphasizes the importance of verifying potential solutions to prevent errors in final results. It’s a crucial habit in mathematics that extends well beyond formal exercises.

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