Răspuns:
m = -3
Explicație pas cu pas:
x²- (2m+3)·x + m² = 0 ; x₁,₂ ∈ C => Δ < 0
a = 1 ; b = -(2m+3) ; c = m²
Δ = b²-4ac = [-(2m+3)]²-4·1·m² = 4m²+12m+9 -4m² = 12m+9
=> 12m + 9 < 0 => m < -9/12 => m < -3/4 <=> m ∈ (-∞ ; -3/4) = I
3(x₁+x₂) + x₁·x₂ = 0
x₁+x₂ = -b/a = 2m+3
x₁·x₂ = c/a = m² =>
6m+9 + m² = 0 <=> (m+3)² = 0 => m = -3 ∈ I
#copaceibrainly