Question

factorise 27a3-b3+8c3+18abc

Answer 1

(3a+b+2c)(9a2+b2+4c2-3ab-2bc-6ac)

Answer 2

27a^3-b^3+8c^3+18abc

=(3a+(-b)+2c) {(3a)^2+(-b)^2+2c^2-3a×(-b)-(-b)×2c-3a×2c

=(3a-b+2c) (9a^2+b^2+4c^2+3ab+2bc-ac