\(\Leftrightarrow x=-\dfrac{1}{2}\)
\(\Leftrightarrow2\left(x^2+x+\dfrac{1}{4}\right)=0\Leftrightarrow2\left(x+\dfrac{1}{4}\right)^2=0\Leftrightarrow x=-\dfrac{1}{4}\)
\(2x^2+2x+\dfrac{1}{2}=0\)
\(\Leftrightarrow4x^2+4x+1=0\)
\(\Leftrightarrow\left(2x+1\right)^2=0\)
\(\Leftrightarrow2x+1=0\)
\(\Leftrightarrow2x=-1\)
\(\Leftrightarrow x=-\dfrac{1}{2}\)
Vậy S = {\(-\dfrac{1}{2}\)}
\(2𝑥^2 + 2x +1/2 = 0\)
=\(2x(x+1)=1/2\) hoặc 0
