Verified answer

Houve um pequeno erro de sinal no seu cálculo de delta:

[tex]x^2 - 7x + 10 = 0\\a = 1\\b = -7\\c = 10\\\\\Delta = b^2 - 4ac\\\Delta = (-7)^2 - (4) \cdot (1) \cdot (10) \\\Delta = 49 -(4) \cdot (10)\\\Delta = 49 - 40\\\Delta = 9\\\\x = \dfrac{-b\pm \sqrt{\Delta}}{2a} = \dfrac{-(-7) \pm \sqrt9}{2 \cdot 1} = \dfrac{7\pm3}{2}\\\\\\x_1 = \dfrac{7+3}{2} = \dfrac{10}{2} = 5\\\\x_2 = \dfrac{7-3}{2} = \dfrac{4}{2} = 2\\\\[/tex]

As raízes são 2 e 5.

[tex]\boxed{\boxed{S=\{2, \ 5\}}}[/tex]

Explicação passo a passo:

x² - 7x + 10 = 0

trinomio do segundo grau completo conforme termos ax² + bx+ c

a = +1

b = -7

c = + 10

delta = b² - 4ac = ( -7)² - [ 4 * 1 * 10 ] = 49 - 40 = 9

delta = +-9 ou +-3² ou +-V3² ou +-3 >>>>delta

x =[ -b +- delta ]/2a

x= [ 7 +- 3 ]/2

x1 = ( 7 + 3 )/2 = 8/2 = 4 >>>>>>resposta x1

x2 = ( 7 - 3 )/2 = 4/2 = 2 >>>>>>resposta x2