Multiplying 2 term × 3 terms

 

(a + 7) × (a 2 + 3a + 5)

  = a × (a 2 +3a+5) + 7 × (a 2   + 3a + 5)

  = a × a 2 + a × 3a + a × 5 + 7 × a 2 + 7 × 3a + 7 × 5

  = a 3 + 3a 2 + 5a + 7a 2 + 21a + 35

  = a 3 + (3a 2 + 7a 2 ) + (5a + 21a) + 35

  = a 3 + 10a 2 + 26a + 35

 

(x + 2) × (x 2 + 4x + 4)

  = 𝑥 × (x 2 + 4x + 4) + 2 × (x 2   + 4𝑥 + 4)

  = 𝑥 × x 2 + 𝑥 × 4𝑥 + 𝑥 × 4 + 2 × x 2 + 2 × 4𝑥 + 2 × 4

  = x 3 + 4x 2 + 4x + 2x 2 + 8x + 8

  = x 3 + 4x 2 + 2x 2 + 4x + 8x + 8

  = x 3 + 6x 2 + 12x + 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.