[tex] {x}^{2} - 8x + 15 = 0[/tex]
A= 1 B= -8 C= 15
[tex]delta = {b}^{2} - 4.a.c[/tex]
[tex]delta = ( - 8) {}^{2} - 4.1.15[/tex]
[tex]delta = 64 - 60[/tex]
[tex]delta = 4[/tex]
[tex]x = \frac{ - b \frac{ + }{ - } \sqrt{delta} }{2.a} [/tex]
[tex]x = \frac{- ( - 8) \frac{ + }{ - } \sqrt{4} }{2.1}[/tex]
[tex]x1 = \frac{8 + 2}{2} = \frac{10}{2} = 5[/tex]
[tex]x2 = \frac{8 - 2}{2} = \frac{6}{2} = 3[/tex]
Espero ter ajudado!
