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a+b=3

a*b=2

Demonstrati ca a^3+b^3=9


Răspuns :

a³+b³=(a+b)(a²-ab+b²)=3(5-2)=3*3=9
(a+b)²=a²+2ab+b²
3²=a²+b²+2*2
a²+b²=9-4=5