Respuesta :

Hello here is a solution :

x²+6x+8 = x² +6x+(9-1)
              = (x²+6x +9) -1 
              =( x² +2(3)(x) +3² )-1 
by identite : a²+2ab+b² = (a+b)²
x²+6x+8 = (x+3)² -1²
by identite : a²-b² = (a-b)(a+b)

x²+6x+8 = (x+3+1)(x+3-1) 
x²+6x+8 = (x+4)(x+2)