Question

if x+y = 10 and xy = 25 find the value of x³ + y³

Answer 1

$x ^{3} + y ^{3 } = (x + y) ^{3 } + 3xy(x + y)$
put value of x+y=10 and xy=25
$x ^{3} + y ^{3} = 10 ^{3} + 3 \times 25 \times 10 = 1000 + 750 = 1750$