Question

What is the value of (x + y)³ - 3xy (x + y)

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Answer 1

Step-by-step explanation:

(1) x+y=1 (Given)

Taking cubes of both sides,

(x+y)^3=1^3

Or, x^3 +y^3 + 3xy(x+y)=1

Substituting for x+y = 1 from eq.(1) on the LHS, we get the answer

x^3 +y^3 + 3xy =1