Question

Questão 4: A menor das raízes da equação x2 + X - 12 = 0 é:
3
4
-3
-4​

Answer 1

• Equação de 2° grau

• Para questões como essa temos 4 fórmulas diferentes para responder
• Vamos pela forma de completar o quadrado.

$\sf x^2+x-12=0\\\\\\\sf x^2+x-12=0\\\\\\\sf x^2+x-12-(-12)=-(-12)\\\\\\\sf x^2+x=-(-12)\\\\\\\sf x^2+x=12\\\\\\\sf\displaystyle x^2+x+\left(\frac{1}{2} \right)^2=12+\left(\frac{1}{2} \right)^2\\\\\\\sf x^2+x+\frac{1}{4} =12+\frac{1}{4} \\\\\\\sf x^2+x+\frac{1}{4}=\frac{49}{4} \\\\\\\sf \left(x+\frac{1}{2} \right)^2=\sqrt{\frac{49}{4} } \\\\\\\sf x+\frac{1}{2}=\frac{7}{2} \\\\\\\sf x+\frac{1}{2}=-\frac{7}{2} \\\\\\\boxed{\sf S=\{ 3,-4\}}$

Menor raiz 3 <<<<<