Ex 4.3, 3 - Chapter 4 Class 10 Quadratic Equations - Part 3

Ex 4.3, 3 - Chapter 4 Class 10 Quadratic Equations - Part 4
Ex 4.3, 3 - Chapter 4 Class 10 Quadratic Equations - Part 5

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Ex 4.3 ,3 Find the roots of the following equations: (ii) 1/(𝑥 + 4)−1/(𝑥 − 7)=11/30,𝑥≠−4, 7 1/(𝑥 + 4)−1/(𝑥 − 7)=11/30 ((𝑥 − 7) − (𝑥 + 4))/((𝑥 + 4)(𝑥 − 7)) = 11/30 (𝑥 − 7 − 𝑥 − 4)/((𝑥 + 4)(𝑥 − 7)) = 11/30 (−11)/((𝑥 + 4)(𝑥 − 7))=11/30 −(11 × 30)/11=(𝑥+4)(𝑥−7) –30 = (x + 4) (x – 7) (x + 4) (x – 7) = –30 x (x – 7) + 4 (x – 7) = –30 x2 – 7x + 4x – 28 = –30 x2 – 3x – 28 = –30 x2 – 3x – 28 + 30 = 0 x2 – 3x + 2 = 0 Factorizing by quadratic method Comparing with ax2 + bx + c = 0 Here a = 1, b = – 3, c = 2 We know that D = b2 – 4ac D = ( – 3)2 – 4×1×2 D = 9 – 8 D = 1 Hence roots to equation are x = (− 𝑏 ± √𝐷)/2𝑎 Putting the values x = (− (− 3) ± √1)/(2 × 1) x =(3 ± 1)/2 Solving Hence x = 2 and x = 1 are the roots of the equation

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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