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Mathematics

Given a polynomial f(x) = 2x3 - 7x2 - 5x + 4

Assertion (A): (x - 1) is not factor of f(x).

Reason (R): f(1) = -6.

  1. Assertion (A) is true, but Reason (R) is false.

  2. Assertion (A) is false, but Reason (R) is true.

  3. Both Assertion (A) and Reason (R) are correct, and Reason (R) is the correct reason for Assertion (A).

  4. Both Assertion (A) and Reason (R) are correct, and Reason (R) is incorrect reason for Assertion (A).

Factorisation

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Answer

Given a polynomial f(x) = 2x3 - 7x2 - 5x + 4

By the Factor Theorem, (x - r) is a factor of f(x) if and only if f(r) = 0.

(x - 1) is a factor of f(x) if and only if f(1) = 0.

f(1) = 2 . (1)3 - 7 . (1)2 - 5 . (1) + 4

= 2 - 7 - 5 + 4 = -6.

Thus, (x - 1) is not a factor of f(x).

So, Both Assertion (A) and Reason (R) are correct, and Reason (R) is the correct reason for Assertion (A).

Hence, option 3 is the correct option.

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