Question

$( x^{2} -5x+2)( x^{2} -5x-1)=28$

Answer 1

$(x^{2} -5x+2)(x^{2} -5x-1)=28, \\ x^{2} -5x=a, \\ (a+2)(a-1)=28, \\ a^2+a-30=0, \\ a_1=-6, a_2=5; \\ x^2-5x+6=0, \\ x_1=2, x_2=3; \\ x^2-5x-5=0, \\ D=45, \\ x_3= \frac{5-3\sqrt{5}}{2} , x_4= \frac{5+3\sqrt{5}}{2}.$