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Basic operations, simple factors, factor Theorem, Remainder Theorem, Division of polynomials.

If x + y = 7 and xy = 6,
the value of (x3 + y3) is : 

Option:
A. 91
B. 133
C. 217
D. 343
Answer: C . 217

Justification:

-> x3 + y3
= (x + y)3 - 3xy (x + y)
= (7)3 - 3(6)(7)
= 343 - (3 x 6 x 7)
= 217

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