Ex 9.5, 8 - Using (x + a) (x + b) = x^2 + (a + b) x + ab, find (i) 103

Ex 9.5, 8 - Chapter 9 Class 8 Algebraic Expressions and Identities - Part 2
Ex 9.5, 8 - Chapter 9 Class 8 Algebraic Expressions and Identities - Part 3 Ex 9.5, 8 - Chapter 9 Class 8 Algebraic Expressions and Identities - Part 4 Ex 9.5, 8 - Chapter 9 Class 8 Algebraic Expressions and Identities - Part 5

  1. Chapter 9 Class 8 Algebraic Expressions and Identities
  2. Serial order wise

Transcript

Ex 9.5, 8 Using (๐‘ฅ+๐‘Ž)(๐‘ฅ+๐‘)=๐‘ฅ^2+(๐‘Ž+๐‘)๐‘ฅ+๐‘Ž๐‘ , find (i) 103 ร— 104 103 ร— 104 = (100+3) ร—(100+4) (๐‘ฅ+๐‘Ž)(๐‘ฅ+๐‘)=๐‘ฅ^2+(๐‘Ž+๐‘)๐‘ฅ+๐‘Ž๐‘ Putting ๐‘ฅ = 100 , ๐‘Ž = 3 & ๐‘ = 4 (๐‘ฅ+๐‘Ž)(๐‘ฅ+๐‘)=๐‘ฅ^2+(๐‘Ž+๐‘)๐‘ฅ+๐‘Ž๐‘ Putting ๐‘ฅ = 100 , ๐‘Ž = 3 & ๐‘ = 4 Ex 9.5, 8 Using (๐‘ฅ+๐‘Ž)(๐‘ฅ+๐‘)=๐‘ฅ^2+(๐‘Ž+๐‘)๐‘ฅ+๐‘Ž๐‘ , find (ii) 5.1 ร— 5.2 5.1 ร— 5.2 = (5+0.1)ร—(5+0.2) (๐‘ฅ+๐‘Ž)(๐‘ฅ+๐‘)=๐‘ฅ^2+(๐‘Ž+๐‘)๐‘ฅ+๐‘Ž๐‘ Putting ๐‘ฅ = 5 , ๐‘Ž = 0.1 & ๐‘ = 0.2 = (5)^2+(0.1+0.2)(5)+(0.1)(0.2) = 25+(0.3)5+(0.1ร—0.2) = 25+3/10ร—5+(1/10ร—2/10) = 25+(15/10)+2/100 = 25+1.5+0.02 = ๐Ÿ๐Ÿ”.๐Ÿ“๐Ÿ Ex 9.5, 8 Using (๐‘ฅ+๐‘Ž)(๐‘ฅ+๐‘)=๐‘ฅ^2+(๐‘Ž+๐‘)๐‘ฅ+๐‘Ž๐‘ , find (iii) 103 ร— 98 103 ร—98 = (100+3)ร—(100โˆ’2) = (100+3)ร—[100+(โˆ’2)] (๐‘ฅ+๐‘Ž)(๐‘ฅ+๐‘)=๐‘ฅ^2+(๐‘Ž+๐‘)๐‘ฅ+๐‘Ž๐‘ Putting ๐‘ฅ = 100 , ๐‘Ž = 3 & ๐‘ = โˆ’2 = (100)^2+(3+2)(100)+(3)(โˆ’2) = 10000+100โˆ’6 = 10000+94 = ๐Ÿ๐ŸŽ๐ŸŽ๐Ÿ—๐Ÿ’ Ex 9.5, 8 Using (๐‘ฅ+๐‘Ž)(๐‘ฅ+๐‘)=๐‘ฅ^2+(๐‘Ž+๐‘)๐‘ฅ+๐‘Ž๐‘ , find (iv) 9.7 ร— 9.8 9.7 ร—9.8 = (10โˆ’0.3)ร—(10โˆ’0.2) = (10+(โˆ’0.3))ร—[10+(โˆ’0.2)] (๐‘ฅ+๐‘Ž)(๐‘ฅ+๐‘)=๐‘ฅ^2+(๐‘Ž+๐‘)๐‘ฅ+๐‘Ž๐‘ Putting ๐‘ฅ = 10 , ๐‘Ž = โˆ’0.3 & ๐‘ = โˆ’0.2 = (10)^2+(โˆ’0.3โˆ’0.2)(10)+(โˆ’0.3)(โˆ’0.2) = 100+(โˆ’0.5ร—10)+(0.3ร—0.2) = 100โˆ’(5/10ร—10)+(3/10ร—2/10) = 100โˆ’5+6/100 = 95+0.06 = ๐Ÿ—๐Ÿ“.๐ŸŽ๐Ÿ”

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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.