Mathematics
Using factor theorem, show that (x - 2) is a factor of x3 + x2 - 4x - 4. Hence, factorise the polynomial completely.
Factorisation
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Answer
By factor theorem, (x - a) is a factor of f(x), if f(a) = 0.
f(x) = x3 + x2 - 4x - 4
(x - 2) is a factor of f(x), if f(2) = 0
Hence, (x - 2) is a factor of x3 + x2 - 4x - 4.
Now, factorizing x3 + x2 - 4x - 4,
Hence, x3 + x2 - 4x - 4 = (x - 2)(x + 1)(x + 2).
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