(x^2-4x+1)(x^2-4x+2)=12 помогите решить

Пусть x^2 - 4x+1 = tt (t + 1) = 12t^2  + t - 12 = 0 D = 1 + 48 = 49t1  =( - 1 + 7)/2 = 6/2 = 3;t2 = ( - 1 -  7)/2 = - 8/2 = - 4;1) x^2 - 4x + 1 = 3x^2 - 4x + 1 - 3 = 0 x^2 - 4x  - 2 =  0D = 16 + 8 = 24√D = 2√6x1 = ( 4 + 2√6)/2 = 2 + √6;x2 = ( 4 - 2√6)/2 = 2 - √6;2) x^2 - 4x + 1 = - 4x^2 - 4x + 5 = 0 D = 16 - 20 = - 4 нет решений