# Example 9 - Chapter 12 Class 7 Algebraic Expressions

Last updated at April 8, 2019 by Teachoo

Last updated at April 8, 2019 by Teachoo

Transcript

Example 9 Find the value of the following expressions for a = 3, b = 2. (i) a + b a + b Putting a = 3 , b = 2 = 3 + 2 = 5 Example 9 Find the value of the following expressions for a = 3, b = 2. (ii) 7a – 4b 7a – 4b Putting a = 3, b = 2 = 7(3) − 4(2) = 21 − 8 = 13 Example 9 Find the value of the following expressions for a = 3, b = 2. (iii) a2 + 2ab + b2 a2 + 2ab + b2 Putting a = 3, b = 2 = (3)3 − (2)3 = (3) − 2 (3) (2) + (2)2 = 21 + 4 = 25 Example 9 Find the value of the following expressions for a = 3, b = 2. (iv) a3 – b3 a3 – b3 Putting a = 3, b = 2 = (3)3 − (2)3 = (3 × 3 × 3) − (2 × 2 × 2) = 27 − 8 = 19

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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.