a) E(-1)=(-1⁴+4)/(-1+1)²+1=(1+4)/(x+1)=5/1=5
b)E(x)=(x²+4)/[(x+1)²+1]=(x⁴+4)/(x²+2x+1+1)=(x⁴+4)/(x²+2x+2)=
=[(x²-2x+2)(x²+2x+2)]/(x²+2x+2)=simplificam cu x²+2x+2=
=x²-2x+2
c) x²-2x+2=0
(x-1)(x-1)=0
x₁=x₂=1
d) E(m)=(m⁴+4)/[(m+1)²+1=(m⁴+4)/(m²+2m+2)=
=[(m²-2m+2)(m²+2m+2)]/(m²+2m+2)=se simplif=m²-2m+2
E(m)-m=m²-2m+2-m=m²-m+2