X^4 - 7X^2 + 12 = 0 ----------------------X^2 = A ( A > 0 ) A^2 - 7A + 12 = 0D = 49 - 48 = 1 ; √ D = 1 A1 = ( 7 + 1 ) : 2 = 4 A2 = 6 : 2 = 3 ----------------X^2 = A -----------X^2 = 4 X1 = 2 X2 = ( - 2 ) ----------X^2 = 3 X3 = √ 3 X4 = - √ 3===========Уравнение 2 X^4 - 11X^2 + 18 = 0---------X^2 = A ( A > 0 )A^2 - 11A + 18 = 0D = 121 - 72 = 49 ; √ D = 7A1 = ( 11 + 7) : 2 = 9 A2 = 4 : 2 = 2 -----------X1 = 3X2 = - 3 X3 = √ 2X4 = - √ 2