x + y = 2, x² + y² = 4 হলে, x³ + y³ = কত?

x² + y² = 4
x + y = 2
আমরা জানি,
(x + y)² = x² + y² + 2xy
Or, 2² = 4 + 2xy
Or, 2xy = o
Or, xy = o
প্রদত্ত রাশি,
x³ + y³ = ( x + y)³ – 3xy(x + y)
= 2³ – 3.0.2
= 8 – o
= 8