Q16 of 30 Page 2

Factorise
(i) x3 + 9x2+ 27x + 27
(ii) x3 – 9x2y + 27xy2 – 27y3

(i) x3+9x2+ 27x + 27 
            = (x)3+ 3(x)2(3)+3(x)(3)2 + (3)3
            = (2x + 3)3
(ii) x3–9x2y + 27xy2 – 27y3
               = x3–3(x)2(3y)+3(x)(3y)2 – (3y)3
               = (x – 3y)3

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