(х-3)(х+2)(х-6)(х-1)+56=0

   1. Введем переменную:

• x - 2 = y;

• (х - 3)(х + 2)(х - 6)(х - 1) + 56 = 0;
• (х + 2)(х - 1)(х - 3)(х - 6) + 56 = 0;
• (y + 4)(y + 1)(y - 1)(y - 4) + 56 = 0;
• (y^2 - 1)(y^2 - 16) + 56 = 0;
• (y^2 - 8,5 + 7,5)(y^2 - 8,5 - 7,5) + 56 = 0;
• (y^2 - 8,5)^2 - 7,5^2 + 56 = 0;
• (y^2 - 8,5)^2 - 56,25 + 56 = 0;
• (y^2 - 8,5)^2 - 0,25 = 0;
• (y^2 - 8,5)^2 - 0,5^2 = 0;
• (y^2 - 8,5 + 0,5)(y^2 - 8,5 - 0,5) = 0;
• (y^2 - 8)(y^2 - 9) = 0.

   2. Приравняем множители к нулю:

• [y^2 - 8 = 0;
  [y^2 - 9 = 0;
• [y^2 = 8;
  [y^2 = 9;
• [y = 22;
  [y = 3;
• [x - 2 = 22;
  [x - 2 = 3;
• [x = 2 22;
  [x = 2 3;
• [x = 2 22;
  [x = -1;
  [x = 5.

   Ответ: 2 22; -1; 5.