Question

Find the value of :
(i)x³+y³-12xy+64, when x+y= -4 .

Answer 1

heya

✴ ur answer is in the attachment

✴ refer it.

✒ hope it helps u..!!

thnkq

Answer 2

x³ + y³ - 12xy + 64

= x³ + y³ + 4³ - 3(4xy)                      

...(As 64 = 4³)

= (x + y + 4)(x² + y² + 4²  - xy - 4y - 4x)    

...[As x³ + y³ + z³ - 3xyz = (x + y + z)(x² + y² + z² - xy - yz - xz]

x + y = - 4

(Given)

= (- 4 + 4) * (x² + y² + 4²  - xy - 4y - 4x)

= 0 * (x² + y² + 4²  - xy - 4y - 4x)

= 0