Question

6- Dada a expressão x^2 - x -12 ( equação do 2° grau ), quais são as raízes?
X =2
X' = -1 e X '' = 0
X' = 5 e X'' = 4
X' = 4 e X'' = -3
X' = 2 e X ''' = 3

Answer 1

$x=\frac{-b\pm\sqrt{b^2-4ac} }{2a} =\frac{-(-1)\pm\sqrt{(-1)^2-4\cdot1\cdot(-12)}}{2\cdot1} =\frac{1\pm\sqrt{1+48}}{2} =\frac{1\pm\sqrt{49}}{2} =\frac{1\pm7}{2} \\\\ x'=\frac{1+7}{2}=\frac{8}{2}=4 \\\\\\ x'=\frac{1-7}{2}=\frac{-6}{2}=-3 \\\\\\S=\{-3, 4\}$