Sagot :
f(x)=(x+5)²(x-1)
=(x-1)(x²+10x+25)
=x²(x-1)+10x(x-1)+25(x-1)
=x³-x²+10x²-10x+25x-25
=x³+9x²+15x-25
=(x-1)(x²+10x+25)
=x²(x-1)+10x(x-1)+25(x-1)
=x³-x²+10x²-10x+25x-25
=x³+9x²+15x-25
[tex](x+5)^2(x-1)=\\
(x^2+10x+25)(x-1)=\\
x^3-x^2+10x^2-10x+25x-25=\\
x^3+9x^2+15x-25[/tex]