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


Transcript

Ex 14.4, 10 Find and correct the errors in the following mathematical statements. Substituting x = – 3 in (a) π‘₯^2 + 5x + 4 gives γ€–"(– 3)" γ€—^2+ 5 (– 3) + 4 = 9 + 2 + 4 = 15 π‘₯^2 + 5x + 4 Putting x = βˆ’3 = γ€–(βˆ’3)γ€—^2 + 5 (βˆ’3) + 4 = (βˆ’3 Γ— βˆ’3) βˆ’ (5 Γ— 3) + 4 = 9 βˆ’ 15 + 4 = βˆ’ 2 So, (–3)2 + 5(–3) + 4 = –2 is the correct statement Ex 14.4, 10 Find and correct the errors in the following mathematical statements. Substituting x = – 3 in (b) π‘₯^2 – 5x + 4 gives γ€–"(– 3)" γ€—^2– 5 ( – 3) + 4 = 9 – 15 + 4 = – 2 π‘₯^2 + 5x + 4 Putting x = βˆ’3 = γ€–(βˆ’3)γ€—^2 βˆ’ 5 (βˆ’3) + 4 = (βˆ’3 Γ— βˆ’3) + (5 Γ— 3) + 4 = 9 + 15 + 4 = 28 So, (–3)2 – 5(–3) + 4 = 28 is the correct statement Ex 14.4, 10 Find and correct the errors in the following mathematical statements. Substituting x = – 3 in (c) π‘₯^2+ 5x gives γ€–"(– 3)" γ€—^2+ 5 (–3) = – 9 – 15 = – 24 π‘₯^2 + 5x Putting x = βˆ’3 = γ€–(βˆ’3)γ€—^2 + 5 (βˆ’3) = (βˆ’3 Γ— βˆ’3) βˆ’ (5 Γ— 3) = 9 βˆ’ 15 = βˆ’6 So, (–3)2 + 5(–3) = –6 is the correct statement

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Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths and Science at Teachoo.