Question 1094589
Factorise:
27b^3-a^3-3a^2-3a-1
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Notice that (a^3 + 3a^2 + 3a + 1) = (a+1)^3
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So it's a difference of 2 cubes.
a^3 - b^3 = (a-b)*(a^2 + ab + b^2)