Question

If x/y + y/x = -1, then, the value of x³ - y³ is

Answer 1

Answer:

If x + y = a and xy = b² , then the value of x³ – x²y - xy² + y³ in terms of a and b is :

(a² + 4b²)a

a³ – 3b²

a³ - 4b²a

a³ + 3b²

Correct Option: C

x3 - x2y - xy2 + y3 = x3 + y3 - x2y - xy2

= (x + y)3 - 3xy(x + y) – xy(x + y)

= (x + y)3 - 4xy(x + y) = a3 - 4b2a

Answer 2

Answer:

0

Step-by-step explanation:

x/y+y/x = -1

now, taking LCM of x and y

(x²+y²)/xy = -1

x²+y² = -xy {transposing xy to RIGHT}

x²+y²+xy=0 ....(Eq-1)

now x³-y³= (x-y)(x²+xy+y²)

so, (x-y)(0) { from (eq - 1)}

therefore, x³-y³= 0