Which of the following is/are not a quadratic equation?
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x2 + √2 x + 7 = 0
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x + 3/x = x2
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x2 + √5 x -18 = 0
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x2 – ix + 7 = 0 i = √-1
Reveal answer
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B
Correct answer
Explanation
A quadratic equation must be of the form ax^2 + bx + c = 0 where a is not 0. Option B: x + 3/x = x^2 becomes x^2 + 3 = x^3, which is a cubic equation, not quadratic.
AI explanation
A quadratic equation must be a polynomial of degree two, meaning variables cannot have negative or fractional exponents. In the equation x + 3/x = x2, the term 3/x can be rewritten as 3x-1, which is a negative exponent and therefore not a polynomial. Rearranging it gives -x2 + x + 3x-1 = 0, confirming it is not a quadratic equation.