Check sibling questions

Ex 14.4, 10 - Substituting x = -3 in (a) x^2 + 5x + 4 gives (- 3)^2

Ex 14.4, 10 - Chapter 14 Class 8 Factorisation - Part 2
Ex 14.4, 10 - Chapter 14 Class 8 Factorisation - Part 3

Learn in your speed, with individual attention - Teachoo Maths 1-on-1 Class


Transcript

Question 10 Find and correct the errors in the following mathematical statements. Substituting x = – 3 in (a) 𝑥^2 + 5x + 4 gives 〖"(– 3)" 〗^2+ 5 (– 3) + 4 = 9 + 2 + 4 = 15 𝑥^2 + 5x + 4 Putting x = −3 = 〖(−3)〗^2 + 5 (−3) + 4 = (−3 × −3) − (5 × 3) + 4 = 9 − 15 + 4 = − 2 So, (–3)2 + 5(–3) + 4 = –2 is the correct statement Question 10 Find and correct the errors in the following mathematical statements. Substituting x = – 3 in (b) 𝑥^2 – 5x + 4 gives 〖"(– 3)" 〗^2– 5 ( – 3) + 4 = 9 – 15 + 4 = – 2 𝑥^2 + 5x + 4 Putting x = −3 = 〖(−3)〗^2 − 5 (−3) + 4 = (−3 × −3) + (5 × 3) + 4 = 9 + 15 + 4 = 28 So, (–3)2 – 5(–3) + 4 = 28 is the correct statement Question 10 Find and correct the errors in the following mathematical statements. Substituting x = – 3 in (c) 𝑥^2+ 5x gives 〖"(– 3)" 〗^2+ 5 (–3) = – 9 – 15 = – 24 𝑥^2 + 5x Putting x = −3 = 〖(−3)〗^2 + 5 (−3) = (−3 × −3) − (5 × 3) = 9 − 15 = −6 So, (–3)2 + 5(–3) = –6 is the correct statement

Ask a doubt
Davneet Singh's photo - Co-founder, Teachoo

Made by

Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.