Pentru a aduce expresia la o alta forma, asociem un zerou si aflam radacinile x1 si x2 a ecuatiei de gradul ll obtiinute (ax²+bx+c=0). Apoi o descompunem in factori conform regulii :
a(x-x1)(x-x2)
x²-5x+6=0
a=1
b=-5
c=6
∆=b²-4ac
∆= (-5)²-4*1*6=25-24=1
x1= (-b+√∆)/2a=(-(-5)+√1)/2*1=(5+1)/2=6/2=3
x2=(-b²-√∆)/2a=(-(-5)-√1)/2*1=(5-1)/2=4/2=2
deci a(x-x1)(x-x2)=(x-3)(x-2)
Metoda ll -metoda gruparii
x²-5x+6=x²-3x-2x+6=x(x-3)-2(x-3)=(x-3)(x+2)
