Learn all Concepts of Chapter 4 Class 10 (with VIDEOS). Check - Quadratic Equations - Class 10

Ex 4.3, 1 - Find roots by completing the square (i) 2x2 - - Solving by completing square

  1. Chapter 4 Class 10 Quadratic Equations
  2. Serial order wise

Transcript

Ex 4.3 ,1 Find the roots of the following quadratic equations, if they exist, by the method of completing the square: (i) 2x2 โ€“ 7x + 3 = 0 2x2 โ€“ 7x +3 = 0 Dividing by 2 (2๐‘ฅ2 โˆ’ 7๐‘ฅ + 3 = 0)/2=0/2 2๐‘ฅ2/2 โ€“ 7๐‘ฅ/2 + 3/2=0 x2 โ€“ 7๐‘ฅ/2+3/2=0 We know that (a โ€“ b)2 = a2 โ€“ 2ab + b2 Here, a = x & โ€“ 2ab = โ€“ 7๐‘ฅ/2 โ€“ 2xb = โˆ’7๐‘ฅ/2 b = โˆ’7๐‘ฅ/(2(โˆ’2๐‘ฅ)) b = 7/4 Now, in our equation x2 โˆ’7๐‘ฅ/2+3/2=0 Adding and subtracting (7/4)^2 x2 โˆ’7๐‘ฅ/2+3/2+(7/4)^2โˆ’(7/4)^2=0 x2 +(7/4)^2โˆ’7๐‘ฅ/2+3/2โˆ’(7/4)^2=0 (๐‘ฅโˆ’ 7/4)^2+3/2 โˆ’(7/4)^2=0 (๐‘ฅโˆ’ 7/4)^2+3/2โˆ’49/16=0 (๐‘ฅโˆ’ 7/4)^2+(3(8) โˆ’ 49)/16=0 (๐‘ฅโˆ’ 7/4)^2+(24 โˆ’ 49)/16=0 (๐‘ฅโˆ’ 7/4)^2โˆ’25/16=0 (๐‘ฅโˆ’7/4)^2=25/16 (๐‘ฅโˆ’7/4)^2=(5/4)^2 Cancelling square both sides ๐‘ฅโˆ’7/4 = ยฑ 5/4

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Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 10 years. He provides courses for Maths and Science at Teachoo.