Verified answer

x² - 4x + 3 = 0

[tex]x = \frac{ - b + - \sqrt{delta} }{2a} [/tex]

[tex]x = \frac{ - b + - \sqrt{ {b}^{2} - 4ac } }{2a} [/tex]

[tex]x = \frac{ - ( - 4) + - \sqrt{ {4}^{2} - 4.1.3 } }{2.1} [/tex]

[tex]x = \frac{4 + - \sqrt{16 - 12} }{2} [/tex]

[tex]x = \frac{4 + - \sqrt{4} }{2} [/tex]

[tex] x = \frac{4 + - 2}{2} [/tex]

[tex]x1 = \frac{4 - 2}{2} [/tex]

[tex]x1 = \frac{2}{2}[/tex]

x' = 1

[tex]x2 = \frac{4 + 2}{2} [/tex]

[tex]x2 = \frac{6}{2} [/tex]

x'' = 3

S = { 1, 3 }