Question

me ajudem nesta equaçao do 2 grau reduzida

[x+3] [x-3]=4x

Answer 1

$\\ (x + 3)(x - 3) = 4x \\ x^2 - 9 = 4x \\ x^2 - 4x - 9 = 0 \\ \Delta = 16 + 36 \Rightarrow \Delta = 52 \\\\ x = \frac{- b \pm \sqrt{\Delta }}{2a} \Rightarrow x = \frac{4 \pm \sqrt{52}}{2} \Rightarrow x = \frac{4 \pm \sqrt{4 \cdot 13}}{2} \\\\ \boxed{S = \left \{ 2 + \sqrt{13}, 2 - \sqrt{13} \right \}}$