Question

Find the value of x3 + y3 +
9xy- 27 if x+y=3.
$find \: the \: value \: of \: x {2} + y {2} + 9xy - 27if \: x + y = 3$
​

Answer 1

Step-by-step explanation:

x+y = 3

Cubing on both sides,

x^3 + y^3 + 3xy(x+y) = 27

x^3 + y^3 + 9xy =27

Therefore,

x^3 + y^3 +9xy -27 = 0