Question

4) Determine as raízes reais da equação x²- 3x - 4 = 0​

Answer 1

Explicação passo-a-passo:

$x_{1,\:2}=\frac{-\left(-3\right)\pm \sqrt{\left(-3\right)^2-4\cdot \:1\cdot \left(-4\right)}}{2\cdot \:1}\\\\x_{1,\:2}=\frac{-\left(-3\right)\pm \:5}{2\cdot \:1}\\\\x_1=\frac{-\left(-3\right)+5}{2\cdot \:1}=4\\\\x_2=\frac{-\left(-3\right)-5}{2\cdot \:1} = -1\\\\\\x1=4,\:x2=-1$