[tex]W(x) = x^{3}-(a+b)x^{2}-(a-b)x + 3\\\\x_1 = 1\\\\W(1) = 0\\\\1^{3}-(a+b)\cdot1^{3} - (a-b)\cdot1 + 3 = 0\\\\1 - (a+b)\cdot1 - (a-b)+3 = 0\\\\1 - a - b - a + b + 3 = 0\\\\-2a = -4 \ \ /:(-2)\\\\a = 2[/tex]
[tex]x_2 = 3\\\\W(3) = 0\\\\3^{3}-(a+b)\cdot3^{2}-(a-b)\cdot3 +3 = 0 \ \ /:3\\\\3^{2}-(a+b)\cdot3 - (a-b) + 1 = 0\\\\9 - 3a - 3b - a + b + 1 = 0\\\\-4a-2b + 10 = 0 \ \ /:(-2)\\\\2a + b-5 = 0\\\\b = 5-2a\\\\b = 5-2\cdot2\\\\b = 1[/tex]
[tex]W(x) = x^{3}-(2+1)x^{2}-(2-1)x + 3\\\\W(x) = x^{3}-3x^{2}-x+3\\\\W(x) = 0\\\\x^{3}-3x^{2}-x+3 = 0\\\\x^{2}(x-3)-(x-3) = 0\\\\(x-3)(x-1)(x+1) = 0\\\\x-3 = 0 \ \vee \ x - 1 = 0 \ \vee \ x+1 = 0\\\\x = 3 \ \vee \ x = 1 \ \vee \ x = -1\\\\Odp. \ x_3 = -1[/tex]