Question

10x ao quadrado +3x-1=0​

Answer 1

$10 {x}^{2} + 3x - 1 = 0$

$\Delta = {b}^{2} - 4ac \\ \Delta = {3}^{2} - 4 \cdot10 \cdot( - 1) \\ \Delta = 9 + 40 \\ \Delta = 49$

$x = \frac{ - b\pm \sqrt{\Delta} }{2a} \\ \\ x = \frac{ - 3\pm \sqrt{49} }{2 \cdot10 } \\ \\ x = \frac{ - 3\pm7}{20}$

$x_{1} = \frac{ - 3 + 7}{20} = \frac{ {4}^{\color{red} { \div 4}} }{ {20}^{\color{red} { \div 4}} } = \bf{ \frac{1}{5} } \\ \\ x_{2} = \frac{ - 3 - 7}{20} = - \frac{ {10}^{\color{red} { \div 10}} }{ {20}^{\color{red} { \div 10}} } = \bf{ - \frac{1}{2} }$

$\text{S} = \{ - \frac{1}{2} , \: \frac{1}{5} \}$

Espero ter ajudado! :)