Question 2 — slide 5

Question 2 — slide 6

Question 2 — slide 7

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Teachoo Β· Class 10 Explore Class 10

Transcript

Question 2 If 𝑓(π‘₯)=𝑝π‘₯^(2)+π‘žπ‘₯+π‘Ÿ,𝑝≠0 and 𝑝+π‘Ÿ=π‘ž, then one of the zeroes of 𝑓(π‘₯) is: (A) (q)/(p) (B) (r)/(p) (C) βˆ’(r)/(p) (D) βˆ’(q)/(p) Given 𝑓(π‘₯)=𝑝π‘₯^(2)+π‘žπ‘₯+π‘Ÿ And, 𝑝+π‘Ÿ=π‘ž 𝑝+π‘Ÿβˆ’π‘ž=0 π’‘βˆ’π’’+𝒓=𝟎 Comparing it with 𝑓(π‘₯) Putting x = –1 in 𝑓(π‘₯) will give us the same equation Let’s try 𝑓(βˆ’1)=𝑝(βˆ’1)^(2) +π‘ž(βˆ’1)+π‘Ÿ 𝒇(βˆ’πŸ)=π’‘βˆ’π’’+𝒓 Putting π‘βˆ’π‘ž+π‘Ÿ=0 𝒇(βˆ’πŸ)=𝟎 Thus, –1 is a zero of 𝒇(𝒙) We need to find the other zero Now, we know that Product of zeroes = (𝒄)/(𝒂) For equation 𝑓(π‘₯)=𝑝π‘₯^(2)+π‘žπ‘₯+π‘Ÿ 𝐜=𝒓, 𝒂=𝒑 And one zero is –1 Thus, –1 Γ— Second zero = (π‘Ÿ)/(𝑝) Second zero = (βˆ’π’“)/(𝒑) So, correct answer is (C) 𝒇(βˆ’πŸ)=π’‘βˆ’π’’+𝒓 Putting π‘βˆ’π‘ž+π‘Ÿ=0 𝒇(βˆ’πŸ)=𝟎 Thus, –1 is a zero of 𝒇(𝒙) We need to find the other zero Now, we know that Product of zeroes = (𝒄)/(𝒂) For equation 𝑓(π‘₯)=𝑝π‘₯^(2)+π‘žπ‘₯+π‘Ÿ 𝐜=𝒓, 𝒂=𝒑 And one zero is –1 Thus, –1 Γ— Second zero = (π‘Ÿ)/(𝑝) Second zero = (βˆ’π’“)/(𝒑) So, correct answer is (C)

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CA Maninder Singh

CA Maninder Singh is a Chartered Accountant qualified since 2010 and an educator teaching since 2006. At Teachoo, he draws on his accounting and tax experience to explain Accounts, Income Tax and GST through step-by-step lessons and practical examples.

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