Question

cum se descompune x^2+4​

Answer 1

Răspuns:

Explicație pas cu pas:

x²+4 = 0 => x² = -4 => x₁,₂ = ±√(-4) = ±2i = (x+2i)(x-2i)

Answer 2

$x^2+4 = x^2+2^2 = (x+2)^2-4x = (x+2)^2-(\sqrt{4x})^2 = \\ \\ =(x+2-\sqrt{4x})(x+2+\sqrt{4x}) = (x+2-2\sqrt{x})(x+2+2\sqrt{x})\\ \\\text{Dar este adevarata doar cand }x > 0 \\ \\\\\Rightarrow x^2+4 = \Big(|x|+2-2\sqrt{|x|}\Big)\Big(|x|+2+2\sqrt{|x|}\Big)$