Question

13. If x + y + z-0 then x+y+z'is equal to:
(a) 3xyz
(b) - 3xyz
(c) xy
(d)-2xy​

Answer 1

a

Explanation:

(x³ + y³ +z³) - 3xyz = (x + y + z )(x² +y² +z² - xy -yz - zx)

If x +y + z = 0, then

(x³ + y³ +z³) - 3xyz = 0 *(x² +y² +z² - xy -yz - zx)

(x³ + y³ +z³) - 3xyz = 0

(x³ + y³ +z³) = 3xyz