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

Q1. [1] § 4.3 Solution of a Quadratic Equation by Factorisation § 4.4 Nature of Roots § 4.5 Summary
If the discriminant of the quadratic equation $3x^2 - 2x + c = 0$ is 16, then the value of $c$ is :
  1. A 1
  2. B 2
  3. C $-1$
  4. D 0
Previously asked in CBSE board exam
2024 30/4/1 Q4
Generated by claude-sonnet-4-6 · 2026-06-15 10:30 · grounding rag
Model Answer

Option C: $-1$

Here, $a = 3$, $b = -2$, $c = c$. Discriminant $= b^2 - 4ac = (-2)^2 - 4(3)(c) = 4 - 12c = 16$
$\Rightarrow -12c = 12 \Rightarrow c = -1$

Source: Chapter 4, Section 4.4 Nature of Roots

Explanation

The discriminant is $b^2 - 4ac$. Substitute the given values and set equal to 16, then solve for $c$. Students often make a sign error with $-4ac$ — be careful that $4 \times 3 \times c = 12c$, giving $4 - 12c = 16$, so $c = -1$.

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