Multiplying 2 term with 2 terms

 

(3a + 4b) × (2a + 3b)

  = 3a × (2a + 3b) + 4b × (2a + 3b)

  = 3a × 2a + 3a × 3b + 4b × 2a + 4b × 3b

  = 6a 2 + 9ab + 8ba + 12b 2

Since ab = ba

= 6a 2 + 9ab + 8ab + 12b 2

= 6a 2 + ab (9 + 8) + 12b 2

= 6a 2 + 17 ab + 12b 2

 

(x + 2) × (x + 4b)

  = x × (x + 4) + 2 × (x + 4)

  = x × x + 4 × x + 2 × x + 2 × 4

  = x 2 + 4x + 2x + 8

  = x 2 + x (4 + 2) + 8

  = x 2 + 6x + 8

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

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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.