Question

Factorise this expression (iii) 8a³- 27b³

Answer 1

4a cube-3b cube
4a cube-3b cube +3*4a*3b(4a-3b)
=4a cube-3b cube+36ab(4a-3b)
=4a cube-3b cube+144a square b-108a b square
This is the answer of the question which you asked

Answer 2

Answer:

  8a3-27b3 = (2a)3 - (3b)3

==> (2a)3 - (3b)3 = (2a - 3b) ( (2a)2 - (2a)(3b) + (3b)2) )

                            = (2a - 3b) ( 4a2 - 6ab + 9b2 )

             

Step-by-step explanation:

Now, difference of two perfect cubes a and b is a3 - b3 = (a-b) (a2 - ab + b2) and here 8 and 27 both are cubes for 2 and 3 respectively.

So, putting up it into the formula.

We get,

Ans :-  8a3-27b3 = (2a - 3b) ( 4a2 - 6ab + 9b2 )