Slide53.JPG

Slide54.JPG

  1. Chapter 7 Class 10 Coordinate Geometry (Term 1)
  2. Serial order wise

Transcript

Ex 7.1, 8 Find the values of y for which the distance between the points P (2, โ€“ 3) and Q (10, y) is 10 units. Let the points be P (โˆ’2, 3) & Q (10, y) Given that PQ = 10 units By distance formula PQ = โˆš((๐‘ฅ2 โˆ’๐‘ฅ1)2+(๐‘ฆ2 โˆ’๐‘ฆ1)2) x1 = 2, y1 = โˆ’3 x2 = 10, y2 = y PQ = โˆš(( 10 โˆ’2)2+(๐‘ฆโˆ’(โˆ’3))2) 10 = โˆš((8)2+(๐‘ฆ+3)2) Squaring both sides (10)2 = (โˆš((8)2+(๐‘ฆ+3)2))2 (10)2 = (8)2 + (y+ 3)2 100 = 64 + (y+ 3)2 100 = 64 + y2 + 32 + 2 ร— 3 ร— y 100 = 64 + y2 + 9 + 6y 0 = y2 + 6y + 64 + 9 โˆ’ 100 0 = y2 + 6y โ€“ 27 y2 + 6y โ€“ 27 = 0 y2 + 9y โ€“ 3y โ€“ 27 = 0 y(y + 9) โ€“ 3(y + 9) = 0 (y โ€“ 3) (y + 9) = 0 Hence, y = 3 or y = โˆ’9 is the solution

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Davneet Singh
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.