Resposta :
(x * x) - 14 = 5x
x² - 14 - 5x = 0
x² - 5x - 14 = 0
[tex]\frac{-b\pm\sqrt{b^{2}-4ac}}{2a} = \frac{5\pm\sqrt{25+56}}{2a} = \frac{5\pm9}{2}\\ \\ x' = 7\\ x'' = -2[/tex]
[tex]x \cdot x - 14 = 5x \\ x^2 - 5x - 14 = 0 \\ x^2 + 2x - 7x - 14 = 0 \\ x(x + 2) - 7(x + 2) = 0 \\ (x + 2)[x - 7] = 0 \\ (x + 2)(x - 7) = 0 \\ \begin{cases} x + 2 = 0 \Rightarrow \boxed{x = - 2} \\ x - 7 = 0 \Rightarrow \boxed{x = 7} \end{cases}[/tex]
Logo, [tex]\boxed{\boxed{S = \left \{ - 2, 7 \right \}}}[/tex]