


Ex 4.3
Ex 4.3, 1 (ii) Important Deleted for CBSE Board 2022 Exams
Ex 4.3, 1 (iii) Deleted for CBSE Board 2022 Exams
Ex 4.3, 1 (iv) Important Deleted for CBSE Board 2022 Exams
Ex 4.3, 2 (i)
Ex 4.3, 2 (ii)
Ex 4.3, 2 (iii)
Ex 4.3, 2 (iv) Important
Ex 4.3, 3 (i) Important
Ex 4.3, 3 (ii)
Ex 4.3, 4
Ex 4.3, 5
Ex 4.3, 6
Ex 4.3, 7 Important
Ex 4.3, 8 Important
Ex 4.3, 9 Important
Ex 4.3, 10 Important
Ex 4.3, 11
Last updated at Dec. 8, 2020 by Teachoo
Ex 4.3 ,1 Find the roots of the following quadratic equations, if they exist, by the method of completing the square: (i) 2x2 – 7x + 3 = 0 2x2 – 7x +3 = 0 Dividing by 2 (2𝑥2 − 7𝑥 + 3 = 0)/2=0/2 2𝑥2/2 – 7𝑥/2 + 3/2=0 x2 – 7𝑥/2+3/2=0 We know that (a – b)2 = a2 – 2ab + b2 Here, a = x & – 2ab = – 7𝑥/2 – 2xb = −7𝑥/2 b = −7𝑥/(2(−2𝑥)) b = 7/4 Now, in our equation x2 −7𝑥/2+3/2=0 Adding and subtracting (7/4)^2 x2 −7𝑥/2+3/2+(7/4)^2−(7/4)^2=0 x2 +(7/4)^2−7𝑥/2+3/2−(7/4)^2=0 (𝑥− 7/4)^2+3/2 −(7/4)^2=0 (𝑥− 7/4)^2+3/2−49/16=0 (𝑥− 7/4)^2+(3(8) − 49)/16=0 (𝑥− 7/4)^2+(24 − 49)/16=0 (𝑥− 7/4)^2−25/16=0 (𝑥−7/4)^2=25/16 (𝑥−7/4)^2=(5/4)^2 Cancelling square both sides 𝑥−7/4 = ± 5/4