Question

Daca :x³-x²-56x=(x+a)(x+b)(x+c)⇒a+b+c egal cu?

Answer 1

x(x^2 -x-56)= x(a+b+c)

=> a=x^2
b=-x
c=-56

=> a+b+c= X^2+(-x)+(-56)
a+b+c=x^2 -x - 56

X^2=x la patrat

Answer 2

$x[x(x-8)+7(x-8)]=x(x-8)(x+7)$$x^{3}- x^{2} -56x=x( x^{2} -x-56)=x( x^{2} -8x+7x-56)=$x[x(x-8)+7(x-8)]=x(x-8)(x+7), deci a=0, b=-8, c=7, deci a+b+c= -1