Question 8 (iv) - Algebra Identities and Formulas - Chapter 8 Class 8 Algebraic Expressions and Identities

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Ex 9.5, 8 - Chapter 9 Class 8 Algebraic Expressions and Identities - Part 4

Ex 9.5, 8 - Chapter 9 Class 8 Algebraic Expressions and Identities - Part 5

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Question 8 Using (𝑥+𝑎)(𝑥+𝑏)=𝑥^2+(𝑎+𝑏)𝑥+𝑎𝑏 , find (iv) 9.7 × 9.8 9.7 ×9.8 = (10−0.3)×(10−0.2) = (10+(−0.3))×[10+(−0.2)] (𝑥+𝑎)(𝑥+𝑏)=𝑥^2+(𝑎+𝑏)𝑥+𝑎𝑏 Putting 𝑥 = 10 , 𝑎 = −0.3 & 𝑏 = −0.2 = (10)^2+(−0.3−0.2)(10)+(−0.3)(−0.2) = 100+(−0.5×10)+(0.3×0.2) = 100−(5/10×10)+(3/10×2/10) = 100−5+6/100 = 95+0.06 = 𝟗𝟓.𝟎𝟔

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science and Computer Science at Teachoo