📚 CBSE Grade-10 Study Guide Open in the Study Guide single page app →
HomeMathematics

Mathematics — CBSE Class 10 board question

Q1. [1]
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

---

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).

If a question refers to an image, map, graph or diagram that is not shown here, open the Study Guide single page app, go to Library and find the actual CBSE question paper. The original papers are also available on the CBSE website: cbse.gov.in.
Previous-year CBSE Grade 10 board exam questions, organised by subject and chapter, each with a model answer — free to read and print.