Ex 8.3, 4 (b) - Chapter 8 Class 8 Algebraic Expressions and Identities

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Ex 8.3, 4 (b) (b) Simplify a (a2 + a + 1) + 5 and find its value for (i) a = 0, (ii) a = 1 (iii) a = – 1.𝑎 (𝑎^2+𝑎+1)+5 = (𝑎×𝑎^2 )+(𝑎×𝑎)+(𝑎×1)+5 = 𝒂^𝟑+𝒂^𝟐+𝒂+𝟓 (i) For 𝒂=𝟎 Putting 𝑎=0 in expression 𝑎^3+𝑎^2+𝑎+5 = (𝟎)^𝟑+(𝟎)^𝟐+𝟎+𝟓 = 0+0+0+5 = 𝟓 (ii) For 𝒂=𝟏 Putting 𝑎=1 in expression 𝑎^3+𝑎^2+𝑎+5 = 〖(𝟏)〗^𝟑+ (𝟏)^𝟐+𝟏+𝟓 = 1+1+1+5 = 𝟖 (iii) For 𝒂=−𝟏 Putting 𝑎=−1 in expression 𝑎^3+𝑎^2+𝑎+5 = 〖(−𝟏)〗^𝟑+ (−𝟏)^𝟐+(−𝟏)+𝟓 = (−1)^2 × (−1)+(1)+(−1)+5 = 1 × (−1)+1−1+5 = −1+1−1+5 = −2+6 = 𝟒 (iii) For 𝒂=−𝟏 Putting 𝑎=−1 in expression 𝑎^3+𝑎^2+𝑎+5 = 〖(−𝟏)〗^𝟑+ (−𝟏)^𝟐+(−𝟏)+𝟓 = (−1)^2 × (−1)+(1)+(−1)+5 = 1 × (−1)+1−1+5 = −1+1−1+5 = −2+6 = 𝟒