Question

Give correct answer and I will mark your name as brain list

Answer 1

(1)

Given x + y = -4.

On cubing both sides, we get

= > (x + y)^3 = (-4)^3

= > x^3 + y^3 + 3xy(x + y) = -64

= > x^3 + y^3 + 3xy(-4) = -64

=  >x^3 + y^3 - 12xy + 64 = 0.


Therefore the value of x^3 + y^3 - 12xy + 64 = 0.


(2)

Given x = 2y + 6

On cubing both sides, we get

= > x^3 = (2y + 6)^3

= > x^3 = 8y^3 + 216 + 3 * 2y * 6(2y + 6)

=  >x^3 - 8y^3 + 216 + 36y(x)

= > x^3 - 8y^3 - 216 - 36xy = 0.


Therefore x^3 - 8y^3 - 216 - 36xy = 0.



Hope this helps!

Answer 2

Hi,

Please see the attached file!


Thanks