Răspuns :
Daca notezi a=x+1 e simplu:
a^3+a^2-2a=a(a^2+a+2) si revenind dupa substitutie
=(x+1)(x^2+2x+1+x+1-2)=(x+1)(x^2+3x)=x(x+1)(x+3)
a^3+a^2-2a=a(a^2+a+2) si revenind dupa substitutie
=(x+1)(x^2+2x+1+x+1-2)=(x+1)(x^2+3x)=x(x+1)(x+3)
(x+1)³ + (x+1)² - 2(x+1) = (x+1)[(x+1)² + x+1 - 2)] =
= (x+1)(x²+2x+1 + x+1 - 2)=
= (x+1)(x²+3x)=
= (x+1)*x*(x+3) =
= x·(x+1)(x+3)
= (x+1)(x²+2x+1 + x+1 - 2)=
= (x+1)(x²+3x)=
= (x+1)*x*(x+3) =
= x·(x+1)(x+3)