Ex 12.2, 3 - Chapter 12 Class 7 Algebraic Expressions - Part 7

Ex 12.2, 3 - Chapter 12 Class 7 Algebraic Expressions - Part 8

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Question 3 (Method 1) Subtract: (vii) 5a2 – 7ab + 5b2 from 3ab – 2a2 – 2b2 (3ab – 2a2 – 2b2) − (5a2 – 7ab + 5b2 ) = 3ab – 2a2 – 2b2 − 5a2 + 7ab − 5b2 = −2a2 − 5a2 − 2b2 − 5b2 + 3ab + 7ab = a2 (−2 − 5) + b2 (−2 − 5) + ab (3 + 7) = a2 (−7) + b2 (−7) + ab (10) = −7a2 − 7b2 + 10ab Question 3 (Method 2) Subtract: (vii) 5a2 – 7ab + 5b2 from 3ab – 2a2 – 2b2 We need to subtract ((5a2 – 7ab + 5b2 ) from (3ab – 2a2 – 2b2) 5a2 − 7ab + 5b2 from 3ab − 2a2 − 2b2 Answer is 10ab – 7a2 – 7b2

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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