Решите по теореме Виета х^2 -3x+a=0

[latex]x^2 - 3x + a = 0\\\\ x_1 + x_2 = -b, \ x_1x_2 = a, \ x_1^2 + x_2^2 = 65\\\\ (x_1 + x_2)^2 = x_1^2 + 2x_1x_2 + x_2^2\\\\ \frac{1}2\left((x_1 + x_2)^2 - (x_1^2 + x_2^2)\right) = x_1x_2\\\\ \frac{9 - 65}{2} = -28 = a\\\\ x_1 + x_2 = 3 = -4 + 7, \ x_1x_2 = -28 = -4*7\\\\ \boxed{x_1 = -4, \ x_2 = 7}[/latex]