Find the zeroes of the polynomial x² + 4x - 12.

MathsCBSE Class 10 · Basic · Board exam 2023, set 430/6/1 · 2 marks · Very short answer

CBSE Class 10 Mathematics Basic 2023: question 22(b)

Set in the CBSE Class 10 board exam of 2023, paper 430/6/1, section B, question 22(b), for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q22(b) · 2 marks · Very short answerPolynomials

Find the zeroes of the polynomial $x^{2} + 4 x - 12$ .

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 430/6/1.

Hints

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

Hint 1

Find two numbers whose product is −12 and sum is 4.

Hint 2

Those numbers are 6 and −2; factorise and set each factor to zero.

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.

Split the middle term: $x^{2} + 4 x - 12 = x^{2} + 6 x - 2 x - 12 = x (x + 6) - 2 (x + 6) = (x + 6) (x - 2)$
1 mark
Putting each factor equal to zero: $x = - 6$ or $x = 2$ . Zeroes are $- 6$ and $2$ .
1 mark

Answer: $- 6$ and $2$

Where the marks are

Factorises as $(x + 6) (x - 2)$ (1 mark)
States zeroes −6 and 2 (1 mark)

Revise the chapter

Chapter: Polynomials (notes, formulas, where marks are lost and every past question)
Topic: Forming a Quadratic Polynomial from Its Zeros

Practise this chapterBoard-style questions from Polynomials, one at a time, marked against the answer key and marking points.Back to the full paper2023 board paper, set 430/6/1 (Basic): every question, by section.

The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.

CBSE Class 10 Mathematics Basic 2023: question 22(b)

Hints

Step-by-step solution

Revise the chapter

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