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Mathematics — Standard (041) — CBSE Class 10 board question

Q1. [1] § 2.2 Geometrical Meaning of the Zeroes of a Polynomial § 2.3 Relationship between Zeroes and Coefficients of a Polynomial
If one zero of the polynomial $6x^2 + 37x - (k - 2)$ is reciprocal of the other, then what is the value of $k$?
  1. (a) $-4$
  2. (b) $-6$
  3. (c) $6$
  4. (d) $4$
Previously asked in CBSE board exam
2023 30/2/1 Q9
Generated by claude-sonnet-4-6 · 2026-06-15 10:34 · grounding rag
Model Answer

(d) 4

If one zero is $\alpha$ and the other is $\dfrac{1}{\alpha}$, then product of zeroes $= \alpha \cdot \dfrac{1}{\alpha} = 1$.

For $6x^2 + 37x - (k-2)$: product of zeroes $= \dfrac{-(k-2)}{6} = 1 \Rightarrow -(k-2) = 6 \Rightarrow k - 2 = -6 \Rightarrow k = -4$.

Wait — rechecking: $\dfrac{-(k-2)}{6}=1 \Rightarrow k-2=-6 \Rightarrow k=-4$.

(a) −4

Source: Chapter 2, Section 2.3

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Explanation

When one zero is the reciprocal of the other, their product = 1. Use the formula: product of zeroes $= \dfrac{c}{a} = \dfrac{-(k-2)}{6}$. Set this equal to 1 and solve for $k$. The constant term here is $-(k-2)$, so be careful with the sign. This gives $k = -4$, option (a).

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