Polynomials
NCERT Exemplar
CBSE
Grade 10
Question:
The zeroes of the quadratic polynomial $x^2 - 2x - 8$ are:
(a) $-2, 4$
(b) $2, -4$
(c) $2, 4$
(d) $-2, -4$
Step-by-Step Solution
Key Concept: Factorise by splitting the middle term: $x^2 - 4x + 2x - 8 = 0$.
$x^2 - 4x + 2x - 8 = x(x - 4) + 2(x - 4) = (x - 4)(x + 2) = 0$. [0.5 Mark]
$x = 4$ or $x = -2$. Zeroes are $-2, 4$. [0.5 Mark]
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🎯 Official CBSE Marking Scheme:
Correct factorisation: 0.5 Mark
Correct zeroes: 0.5 Mark
Correct Answer: $-2, 4$
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