Misc 9 - Solve 21x2 - 28x + 10 = 0 - Chapter 5 NCERT - Miscellaneous

  1. Chapter 5 Class 11 Complex Numbers
  2. Serial order wise

Transcript

Misc 9 Solve the equation 21๐‘ฅ2 โ€“ 28๐‘ฅ + 10 = 0 21๐‘ฅ2 โ€“ 28๐‘ฅ + 10 = 0 The Above equation of the form ๐‘Ž๐‘ฅ2 + ๐‘๐‘ฅ + ๐‘ = 0 Where a = 21, b = โ€“28, and c = 10 ๐‘ฅ = (โˆ’๐‘ ยฑ โˆš( ๐‘^2 โˆ’ 4๐‘Ž๐‘ ))/2๐‘Ž ๐‘ฅ = (โˆ’ ( โˆ’ 28) ยฑ โˆš((โˆ’28)^2 โˆ’4 ร— 21 ร—10))/(2 ร— 21) = (28 ยฑ โˆš(784 โˆ’ 840))/42 = (28 ยฑ โˆš(โˆ’56))/42 = (28 ยฑ โˆš(โˆ’ 14 ร—4 ))/42 = (28 ยฑ 2โˆš(โˆ’ 14))/42 = (2 [14 ยฑ โˆš(โˆ’ 14) ])/42 = (2 [ 14 ยฑ โˆš(โˆ’ 14) ])/(2 ร— 21) = ( [ 14 ยฑ โˆš(โˆ’ 14) ] )/21 = ( 14 ยฑ โˆš(โˆ’ 1 ร— 14) )/21 = ( 14 ยฑ โˆš(โˆ’ 1) ร—โˆš14)/21 = ( 14 ยฑ โˆš14 ๐‘–)/21 Thus, ๐‘ฅ = ( 14 ยฑ โˆš14 ๐‘–)/21

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Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 8 years. He provides courses for Maths and Science at Teachoo. You can check his NCERT Solutions from Class 6 to 12.