х²+х-5=0
D=1+20=21, х₁=(-1-√21)/2=-1/2-√21/2, х₂=-1/2+√21/2
x₁² *x₂⁴+x₂² *x₁⁴=(-1/2-√21/2)²(-1/2+√21/2)⁴+(-1/2+√21/2)²(-1/2-√21/2)⁴=
=(-1/2-√21/2)²(-1/2+√21/2)² *[(-1/2+√21/2)²+(-1/2-√21/2)²=
=(21/4-1/4) *[1/4-2*1/2*√21/2+21/4+1/4+√21/2+21/4]=
=5² * [44/4]=275