Question 1 - Think and Reflect (Page 73) - Factorisation of Algebraic Expressions Using Identities - Chapter 4 Class 9 - Exploring Algebraic Identities (Ganita Manjari I)

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[Class 9] What if we replace b by – b in (a + b)^2 = a^2 + 2ab + b^2? - Factorisation of Algebraic Expressions Using Identities

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Question 1 - Think and Reflect (Page 73) What if we replace 𝑏 by −𝑏 in (𝑎+𝑏)^2=𝑎^2+2𝑎𝑏+𝑏^2? Our expression is (𝒂+𝒃)^𝟐=𝒂^𝟐+𝟐𝒂𝒃+𝒃^𝟐 Replacing 𝒃 by −𝒃 (𝑎+(−𝑏))^2=𝑎^2+2𝑎(−𝑏) +〖(−𝑏)〗^2 Since (-b)2 = b2 (𝒂−𝒃)^𝟐=𝒂^𝟐−𝟐𝒂𝒃 +𝒃^𝟐 Thus, our expression becomes (𝒂−𝒃)^𝟐=𝒂^𝟐−𝟐𝒂𝒃 +𝒃^𝟐

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