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ajutatima varog descompuneti in factori (x+1)^3-(x-2)^3

Răspuns :

a³-b³=(a-b)(a²+ab+b²)
(x+1)³-(x-2)³ =[
(x+1)-(x-2)][(x+1)²+(x+1)(x-2)+(x-2)²] =
=
(x+1-x+2)(x²+2x+1+x²+x-2x-2+x²-4x+4) =
=3(3x²-3x+3) =9(x²-x+1)