Which of the following values is not a root of \(x^2-64=0\)?
Answer and explanation
Correct answer: 0
Solving \(x^2-64=0\) gives \(x^2=64\), so \(x=\pm8\). Thus 8 and -8 are roots. Also \(\sqrt{64}=8\), so option D represents 8 and is a root. Substituting 0 does not satisfy the equation, so 0 is not a root. Exam tip: for equations of the form \(x^2=a\) remember the solutions are \(x=\pm\sqrt{a}\); \(\sqrt{a}\) by itself denotes the principal (positive) square root.
Frequently asked questions
What is the correct answer to this question?
0
Why is this the correct answer?
Solving \(x^2-64=0\) gives \(x^2=64\), so \(x=\pm8\). Thus 8 and -8 are roots. Also \(\sqrt{64}=8\), so option D represents 8 and is a root. Substituting 0 does not satisfy the equation, so 0 is not a root. Exam tip: for equations of the form \(x^2=a\) remember the solutions are \(x=\pm\sqrt{a}\); \(\sqrt{a}\) by itself denotes the principal (positive) square root.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Quadratic Equations. Topic: Roots of a Quadratic Equation.
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