Question

tìm x

\(x^3+x^2+x+1=0\)

Answer 1

\(x^3+x^2+x+1=0\)

\(\Rightarrow\left(x^3+x^2\right)+\left(x+1\right)=0\)

\(\Rightarrow x.\left(x+1\right)+\left(x+1\right)=0\)

\(\Rightarrow\left(x+1\right).\left(x+1\right)=0\)

\(\Rightarrow\left(x+1\right)^2=0\Rightarrow x+1=0\Rightarrow x=-1\)

Vậy \(x=-1\)

Chúc bạn học tốt!!!

Answer 2

Ta có:x³+x²+x+1=0

<=>(x³+x)+(x²+1)=0<=>x(x²+1)+(x²+1)=0

<=>(x+1)(x²+1)=0

=>x+1=0(vì x²+1>0)=>x=-1

Vậy S={-1}