Which of the following is not a quadratic equation ? (A) (x - 2)² + 1 = 2x - 3 (B) (2x - 1)(x - 3) = (x + 5)(x - 1) (C) x(x + 1) + 8 = (x + 2)(x - 2) (D) 2x + 3/x = 5

MathsCBSE Class 10 · Basic · Board exam 2024, set 430/4/1 · 1 mark · MCQ

CBSE Class 10 Mathematics Basic 2024: question 9

Set in the CBSE Class 10 board exam of 2024, paper 430/4/1, section A, question 9, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q9 · 1 mark · MCQQuadratic Equations

Which of the following is not a quadratic equation ?

(A) $(x - 2)^{2} + 1 = 2 x - 3$
(B) $(2 x - 1) (x - 3) = (x + 5) (x - 1)$
(C) $x (x + 1) + 8 = (x + 2) (x - 2)$
(D) $2 x + \frac{3}{x} = 5$

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 430/4/1.

Hints

Open one hint at a time and try again before the next.

Hint 1

Expand both sides of each equation.

Hint 2

Check whether the $x^{2}$ terms cancel out.

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

In (C), $x^{2} + x + 8 = x^{2} - 4$ , which reduces to $x + 12 = 0$ . This is linear, not quadratic.
1 mark
The other options reduce to equations of degree 2, for example (D) becomes $2 x^{2} - 5 x + 3 = 0$ . So the answer is option (C).

Answer: Option (C)

Where the marks are

Simplifies (C) and shows the $x^{2}$ terms cancel (1 mark)

Revise the chapter

Chapter: Quadratic Equations (notes, formulas, where marks are lost and every past question)
Topic: Standard Form of a Quadratic Equation

Practise this chapterBoard-style questions from Quadratic Equations, one at a time, marked against the answer key and marking points.Back to the full paper2024 board paper, set 430/4/1 (Basic): every question, by section.

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CBSE Class 10 Mathematics Basic 2024: question 9

Hints

Step-by-step solution

Revise the chapter

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