\[3\ и\ \ 5\]
\[x_{1} + x_{2} = 3 + 5 = 8;\]
\[x_{1} \cdot x_{2} = 3 \cdot 5 = 15.\]
\[Уравнение:\ \ \ \]
\[x^{2} - 8x + 15 = 0.\]