Question 3 - Examples - Chapter 4 Class 10 Quadratic Equations

Last updated at December 13, 2024 by

Example 9 - Find roots of 4x2 + 3x + 5 = 0 by completing sq - Solving by completing square

Example 9 - Chapter 4 Class 10 Quadratic Equations - Part 2
Example 9 - Chapter 4 Class 10 Quadratic Equations - Part 3

Remove Ads Share on WhatsApp

Transcript

Question 3 Find the roots of 4x2 + 3x + 5 = 0 by the method of completing the square. 4x2 + 3x + 5 = 0 Dividing by 4 4š‘„2/4+3š‘„/4+5/4=0 x2 + 3š‘„/4+5/4=0 We know that (a + b)2 = a2 + 2ab + b2 Here, a = x & 2ab = 3š‘„/4 2xb = 3š‘„/4 2b = 3/4 b = 3/4Ɨ1/2 b = 3/8 Now, in our equation x2 + 3š‘„/4+5/4=0 Adding and subtracting (3/8)^2 x2 + 3š‘„/4+5/4+(3/8)^2āˆ’(3/8)^2=0 x2 + 3š‘„/4+(3/8)^2+5/4āˆ’(3/8)^2=0 (š‘„+3/8)^2+5/4āˆ’(3/8)^2=0 (š‘„+3/8)^2=(3/8)^2āˆ’5/4 (š‘„+3/8)^2=9/64āˆ’5/4 (š‘„+3/8)^2=(9 āˆ’ 5(16))/64 (š‘„+3/8)^2=(9 āˆ’ 80)/64 (š‘„+3/8)^2=(āˆ’71)/64 Since square of any number cannot be negative So, answer does not exist

Davneet Singh's photo - Co-founder, Teachoo

Made by

Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science and Computer Science at Teachoo