CBSE Class 10 Sample Paper for 2025 Boards - Maths Standard
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CBSE Class 10 Sample Paper for 2025 Boards - Maths Standard
Last updated at Feb. 12, 2025 by Teachoo
This question is similar to Chapter 4 Class 10 Quadratic Equations - Ex 4.3
Please check the question here
https://www.teachoo.com/13145/509/Ex-4.4--1-iii/category/Ex-4.4/
Transcript
Question 11 The roots of the quadratic equation 𝑥^2+𝑥−1=0 are (A) Irrational and distinct (B) not real (C) rational and distinct (D) real and equal x2 + x − 1 = 0 Comparing equation with ax2 + bx + c = 0 a = 1 , b = 1, c = −1 We know that , D = b2 – 4ac = (1)2 – 4 × 1 × (−1) = 1 + 4 = 5 Concept: D < 0 , no real roots D = O , two equal real roots D > 0, two distinct real roots Since D > 0 There are 2 distinct real roots Now using quadratic formula to find roots x = (− 𝑏 ± √𝐷)/2𝑎 Putting values x = (−1 ± √5)/(2 × 1) x = (−𝟏 ± √𝟓)/𝟐 Therefore, the root of the equation are x = (−𝟏 + √𝟓)/𝟐 & x = (−𝟏 − √𝟓)/𝟐 Thus, Roots are irrational Roots are distinct So, the correct answer is (A)
