Question

factorise 24 a cube + 81 b cube​

Answer 1

Answer:

Step-by-step explanation:

Given to factorize 24 a^3 + 81 b^3

               So 3(8 a^3 + 27 b^3)

                 3[(2a)^3 + (3b)^3]

This is in the form of a^3 + b^3 = (a + b)^3 – 3ab(a + b)

Where a = 2a and b = 3b

So  = 3[(2a + 3b)^3 – 3(2a)(3b) (2a + 3b)]

   = 3[(2a + 3b) {(2a + 3b)^2 – 18ab}]

    = 3[2a + 3b{(4a^2 + 9b^2 + 12ab – 18ab)}

    = 3(2a + 3b) (4a^2 + 9b^2 – 6ab)