If x + y + 3 = 0, then find the value of x3 + y3 - 9xy + 9.
Correct Answer :
- 18
Solution :
The correct answer is -18.
Given the equation:
We can rewrite this equation by shifting 3 to the right-hand side:
Now, let us cube both sides of the equation:
Using the algebraic identity for the cube of a sum, , we expand the left-hand side:
Substitute into the equation:
We want to find the value of . By adding 9 to both sides of the equation, we get:
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