a)
x²+7x+12 = 0
x²+4x+3x+12 = 0
x(x+4)+3(x+4) = 0
(x+4)(x+3) = 0
⇒ x ∈ {-4, -3}
b)
x²+4x+4 = 0
(x+2)² = 0
⇒ x = -2
Răspuns:
Explicație pas cu pas:
a.
x^2 + 7 x + 12 = x^2 +3x +4x +12= x ( x +3) +4 (x + 3)= (x+3) (x+4)
b.
x^2 + 4x + 4 =x^2 + 2x + 2x = 4 = x ( x+2) + 2 ( x+2) = (x=2) ( x+2) =( x+2 )^2
