Question

Resolva as equações do 2º grau usando a fórmula geral.
ME AJUDEM POR FAVOR.

Answer 1

a) a = 1 // b = -4 // c = 3

$x=\frac{-b\±\sqrt{b^2-4ac}}{2a} \\\\ x=\frac{-(-4)\±\sqrt{(-4)^2-4*1*3}}{2*1} \\\\ x=\frac{4\±\sqrt{16-12}}{2} \\\\ x=\frac{4\±\sqrt{4}}{2} \\\\ x=\frac{4\±2}{2}$

x = 3 ou x = 1

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b) a = 1 // b = -1 // c = -12

$x=\frac{-b\±\sqrt{b^2-4ac}}{2a} \\\\ x=\frac{-(-1)\±\sqrt{(-1)^2-4*1*(-12)}}{2*1} \\\\ x=\frac{1\±\sqrt{1+48}}{2} \\\\ x=\frac{1\±\sqrt{49}}{2} \\\\ x=\frac{1\±7}{2}$

x = 4 ou x = -3

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c) a = -1 // b = -3 // c = -40

$x=\frac{-b\±\sqrt{b^2-4ac}}{2a} \\\\ x=\frac{-(-3)\±\sqrt{(-3)^2-4*(-1)*(-40)}}{2*(-1)} \\\\ x=\frac{3\±\sqrt{9-160}}{-2} \\\\ x=\frac{3\±\sqrt{-151}}{-2}$

x = $\frac{3+\sqrt{-151}}{-2}$ ou x = $\frac{3-\sqrt{-151}}{-2}$