Question

If x + y = 3 , find the value of x^3+y^3+9xy​

Answer 1

Answer:

If x - y = 3, then what is x^3-y^3-9xy? - Quora. x - y = 3, then (x-y)² = 9, thus x²-2xy+y² = 9. x²+xy+y² = x²-2xy+y² + 3xy, so, x²+xy+y² = 9 + 3xy. Back to our question: we have now the value of x-y and x²+xy+y².