Răspuns:
a)
(x²+y²) (x-y) =x³-x²y+y²x-y³=
=x²(x-1)+y²(x-1)=
=(x-1)(x²+y²)
b)
a(a+1)(a+2)=(a²+a)(a+2)=
=a³+2a²+a²+2a
Sunt 2 cazuri de rezolvare, acum depinde cum ai facut in clasa
1.
=a³+3a²+2a=
=a(a²+3a+2)
2.
=a²(a+2)+a(a+2)=
=(a+2)(a²+a)
c)
(x-y) (x²+xy+y²)
Aici ii formula de calcul prescurtat
=>a³-b³=(a-b) (a²+ab+b²)
Daca nu ai invatat formula, ai jos rezolvarea pas cu pas:
(x-y) (x²+xy+y²) =
=x³+x²y+y²x-yx²-y²x-y³=
=x³+x²y-x²y+y²x-y²x-y³=
=x³-y³
d)
(x²-3x) (x²+3x+9)=
=x⁴+3x³+9x²-3x³-9x²-27x=
=x⁴-27x=
=x(x³-27)
