Question

lf x + y = 12 and xy= 27, find the value
of x3 +y3
​

Answer 1

x + y = 12

xy = 27

Answer is 756

we know that

$(x + y) {}^{2} = {x}^{3} + {y}^{3} + 3xy(x + y)$

12^3 = x^3 + y^3 + 3 × 27 × 12

1728 = x^3 + y^3 + 972

1728 - 972 = x^3 + y^3

756 = x^3 + y^3