Question

x² + x – 7 = 5 me ajudem​

Answer 1

Resposta:

S = {-4 ; 3}

Explicação passo-a-passo:

$x^2 + x - 7 = 5\\x^2 + x - 7 - 5 = 0\\x^2 + x - 12 = 0\\\\delta = b^2 - 4ac = (1)^2 - 4 * (1) * (-12) = 49\\\\x = \frac{-b+-\sqrt{delta} }{2a} = \frac{-1+-\sqrt{49} }{2} = \frac{-1+-7 }{2} \\\\ x_{1} = \frac{-1+7 }{2} = \frac{6}{2} = 3 \\\\ x_{2} = \frac{-1-7 }{2} = \frac{-8}{2} = -4$