Question

if x/y+y/x=-1(x,y=~0)then the value of x power3-y power 3 is
(a)-1
(b)1
(c)0
(d)1/2
​

Answer 1

Answer:

0

x/y + y/x = -1

(x^2+ y^2)/xy = -1

(x^2 + y^2 /xy) +1 = 0

(x^2 + y^2 + xy)/xy = 0

x^2 + y^2 + xy = 0

Multiplying by (x-y)

(x-y)(x^2 + y^2 + xy) = 0

x^3 - y^3 = 0.

[using identity x^3 - y^3 = (x-y)(x^2 + y^2 + xy )]