Question

Resolva as equações do segundo Grau utilizando a formula de Báskara: a) X^2-4x-45=0

Answer 1

Resposta:

x₁ = 9, x₂ = -5

Explicação passo a passo:

$x^2-4x-45=0$

$x_{1,\:2}=\frac{-\left(-4\right)\pm \sqrt{\left(-4\right)^2-4\cdot \:1\cdot \left(-45\right)}}{2\cdot \:1}$

$x_{1,\:2}=\frac{-\left(-4\right)\pm \:14}{2\cdot \:1}$

$x_1=\frac{-\left(-4\right)+14}{2\cdot \:1}=\frac{4+14}{2\cdot \:1}=\frac{18}{2\cdot \:1}=\frac{18}{2}=9$

$x_2=\frac{-\left(-4\right)-14}{2\cdot \:1}=\frac{4-14}{2\cdot \:1}=\frac{-10}{2\cdot \:1}=\frac{-10}{2}=-\frac{10}{2}=-5$

$x_1=9,\:x_2=-5$