For which value(s) of p, will the lines represented by the following pair of linear equations be parallel

  3x − y − 5 = 0

  6x −2y − p = 0

(a) all real values except 10  (b) 10  (c) 5/2  (d) 1/2

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Question 4 For which value(s) of p, will the lines represented by the following pair of linear equations be parallel 3x − y − 5 = 0 6x − 2y − p = 0 (a) all real values except 10 (b) 10 (c) 5/2 (d) 1/2 Given lines 3x − y − 5 = 0 and 6x − 2y − p = 0 3x − y − 5 = 0 Comparing with a1x + b1y + c1 = 0 a1 = 3, b1 = –1, c1 = –5 6x − 2y − p = 0 Comparing with a2x + b2y + c2 = 0 a2 = 6, b2 = –2, c2 = –p Now, Since lines are parallel 𝑎_1/𝑎_2 = 𝑏_1/𝑏_2 ≠ 𝑐_1/𝑐_2 Comparing 𝑎_1/𝑎_2 = 𝑏_1/𝑏_2 ≠ 𝑐_1/𝑐_2 3/6=(−1)/(−2) ≠ (−5)/(−𝑝) 1/2=1/2 ≠ 5/𝑝 Therefore, 1/2 ≠ 5/𝑝 p ≠ 5 × 2 p ≠ 10 So, correct answer is (a) – all real values except 10

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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.