Polynomials
NCERT Exemplar Ch 02
CBSE_NCERT_EXEMPLAR_CH02
Grade 10
Question:
If one zero of the quadratic polynomial $x^2 + 3x + k$ is $2$, then the value of $k$ is:
$10$
$-10$
$-7$
$-2$
Step-by-Step Solution
Key Concept: Substitute $x = 2$ into $p(x) = 0$.
Stepwise Solution:
$p(2) = 2^2 + 3(2) + k = 0$. [0.5 Mark]
$4 + 6 + k = 0 \Rightarrow 10 + k = 0 \Rightarrow k = -10$. [0.5 Mark]
Marking Scheme:
• Substituting zero into polynomial: 0.5 Mark
• Solving for $k$: 0.5 Mark
Correct Answer: $-10$
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