# Ex 12.3, 3 - Chapter 12 Class 7 Algebraic Expressions

Last updated at Dec. 21, 2018 by Teachoo

Last updated at Dec. 21, 2018 by Teachoo

Transcript

Ex 12.3, 3 Find the value of the following expressions, when x = –1: (i) 2x – 7 2x − 7 Putting x = − 1 = 2 (−1) − 7 = −2 − 7 = −9 Ex 12.3, 3 Find the value of the following expressions, when x = –1: (ii) – x + 2 −x + 2 Putting x = −1 = − (−1) + 2 = 1 + 2 = 3 Ex 12.3, 3 Find the value of the following expressions, when x = –1: (iii) x2 + 2x + 1 x2 + 2x + 1 Putting x = −1 = (−1)2 + 2(−1) + 1 = 1 – 2 + 1 = 2 − 2 = 0 Ex 12.3, 3 Find the value of the following expressions, when x = –1: (iv) 2x2 – x – 2 2x2 – x – 2 Putting x = −1 = 2(−1)2 − (−1) −2 = 2(1) + 1 − 2 = 3 – 2 = 1

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Davneet Singh

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.