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


Ex 9.4, 3 Simplify. (v) (๐‘ฅ+๐‘ฆ)(2๐‘ฅ+๐‘ฆ)+(๐‘ฅ+2๐‘ฆ)(๐‘ฅโˆ’๐‘ฆ) Here, there are 2 expressions 1st expression = (๐‘ฅ+๐‘ฆ)(2๐‘ฅ+๐‘ฆ) 2nd expression = (๐‘ฅ+2๐‘ฆ)(๐‘ฅโˆ’๐‘ฆ) Solving First expression (๐‘ฅ+๐‘ฆ)(2๐‘ฅ+๐‘ฆ) = ๐‘ฅ(2๐‘ฅ+๐‘ฆ)+๐‘ฆ (2๐‘ฅ+๐‘ฆ) = (๐‘ฅร—2๐‘ฅ)+(๐‘ฅร—๐‘ฆ)+(๐‘ฆร—2๐‘ฅ)+(๐‘ฆร—๐‘ฆ) = 2๐‘ฅ^2+๐‘ฅ๐‘ฆ+2๐‘ฆ๐‘ฅ+๐‘ฆ^2 = 2๐‘ฅ^2+๐‘ฅ๐‘ฆ+2๐‘ฅ๐‘ฆ+๐‘ฆ^2 = 2๐‘ฅ^2+3๐‘ฅ๐‘ฆ+๐‘ฆ^2 Solving 2nd expression (๐‘ฅ+2๐‘ฆ)(๐‘ฅโˆ’๐‘ฆ) = ๐‘ฅ(๐‘ฅโˆ’๐‘ฆ)+2๐‘ฆ (๐‘ฅโˆ’๐‘ฆ) = (๐‘ฅร—๐‘ฅ)โˆ’(๐‘ฅร—๐‘ฆ)+(2๐‘ฆร—๐‘ฅ)โˆ’(2๐‘ฆร—๐‘ฆ) = ๐‘ฅ^2โˆ’๐‘ฅ๐‘ฆ+2๐‘ฆ๐‘ฅโˆ’2๐‘ฆ^2 = ๐‘ฅ^2+๐‘ฅ๐‘ฆโˆ’2๐‘ฆ^2 Now, our expression becomes: (๐‘ฅ+๐‘ฆ)(2๐‘ฅ+๐‘ฆ)+(๐‘ฅ+2๐‘ฆ)(๐‘ฅโˆ’๐‘ฆ) = 2๐‘ฅ^2+3๐‘ฅ๐‘ฆ+๐‘ฆ^2+๐‘ฅ^2+๐‘ฅ๐‘ฆโˆ’2๐‘ฆ^2 = 2๐‘ฅ^2+๐‘ฅ^2+3๐‘ฅ๐‘ฆ+๐‘ฅ๐‘ฆ+๐‘ฆ^2โˆ’2๐‘ฆ^2 = ๐Ÿ‘๐’™^๐Ÿ+๐Ÿ’๐’™๐’šโˆ’๐’š^๐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 9 years. He provides courses for Maths and Science at Teachoo.