(x - 2) and (x + 2) are the factors of x3 + x2 - 4x - 4. The third factor of the given polynomial is :
- (a)(x - 1)
- (b)(x - 4)
- (c)(x + 1)
- (d)(x + 4)
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Given,
(x - 2) and (x + 2) are the factors of x3 + x2 - 4x - 4.
⇒ (x - 2)(x + 2) = x2 - 4
Thus, x2 - 4 is also the factor of x3 + x2 - 4x - 4.
$$\begin{array}{l} \phantom{x - 3x)}{\quad x + 1} \\ x^2 - 4\overline{\smash{\big)}\quad x^3 + x^2 - 4x - 4 } \\ \phantom{x^2 + n}\phantom(\underline{\underset{-}{+}x^3 \underset{+}{-}4x} \\ \phantom{x^2 + 3x -])7 + o)()} x^2 - 4 \\ \phantom{x^2 + 3x - ((5) + )}\underline{\underset{-}{+}x^2 \underset{+}{-}4} \\ \phantom{x^2 + 3x - 5) + 24x )}\times \end{array}$$
Thus, x3 + x2 - 4x - 4 = (x2 - 4)(x + 1)
= (x + 2)(x - 2)(x + 1).
Hence, option 3 is the correct option.