Question

factorise 81 x cube minus 24 y cube

Answer 1

Answer:

81x^3 - 24y^3 = 3(27x^3 - 8y^3)

Now,using this identity:

(a-b)^3 + 3ab(b-a) = a^3 - b^3

In ( 27x^3 - 8y^3), a^3 = 27x^3

(a = 3y)

b^3 = -8y^3

(b = - 2y)

So, [3x-(-2y)]^3 + 3.3x.-2y(-2y-3x). = 27x^3 - 8y^3

= (3x+2y)^3 - 18y^2(-2-3y)

Don't forget the '3'

So multiply the factored polynomial with 3 and you'll get:

3[(3x+2y)^3 - 54y^2(-2y-3x) is the factored form of 81 x cube minus 27 y cube.

But don't access prepared answers from various sources instead create them yourself.