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Mathematics

Assertion (A): x3 + 2x2 - x - 2 is a polynomial of degree 3.

Reason (R): x + 2 is a factor of the polynomial.

  1. Both A and R are true, and R is the correct explanation of A.

  2. Both A and R are true, but R is not the correct explanation of A.

  3. A is true, but R is false.

  4. A is false, but R is true.

Factorisation

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Answer

Since, the highest value of power of x in the polynomial x3 + 2x2 - x - 2 is 3.

Thus,

x3 + 2x2 - x - 2 is a polynomial of degree 3.

∴ Assertion (A) is true.

By factor theorem,

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

x + 2 = 0

x = -2

Substituting x = -2 in x3 + 2x2 - x - 2, we get :

⇒ (-2)3 + 2(-2)2 - (-2) - 2

⇒ -8 + 2(4) + 2 - 2

⇒ -8 + 8 + 2 - 2

⇒ 0.

∴ Reason (R) is true.

Both A and R are true, but R is not the correct explanation of A.

Hence, Option 2 is the correct option.

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