Question

Daca $x^{3}- x^{2} -56x =(x+a)(a+b)(x+c)$ ,cat este a+b+c?

Answer 1

[tex]x(x^2-x-56)=x(x^2+7x-8x-56)=x[x(x+7)-8(x+7)]=\\ =(x+0)(x+7)(x-8)=(x+a)(x+b)(x+c)\\ a=0;b=7;c=-8\\ a+b+c=0+7-8=-1[/tex]