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Question
Factorise the following:
27 – 125a3 – 135a + 225a2
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Solution
27 – 125a3 – 135a + 225a2
= 33 – (5a)3 – 3(3) (5a) (3 – 5a)
= (3 – 5a)3 ...[Using a3 − b3 − 3ab(a − b) = (a − b)3]
= (3 – 5a)(3 – 5a)(3 – 5a)
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