Question

Giải phương trình

a) \(x^2-2x+1=0\)

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

c)\(x+x^4=0\)

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

e)\(x^2+x-12=0\)

g)\(6x^2-11x-10=0\)

Answer 1

a) Ta có: \(x^2-2x+1=0\)

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

\(\Leftrightarrow x-1=0\)hay x=1

Vậy: S={1}

c) Ta có: \(x+x^4=0\)

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

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

mà \(x^2-x+1>0\forall x\)

nên x(x+1)=0

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x+1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-1\end{matrix}\right.\)

Vậy: S={0;-1}