ĐKXĐ: ...
\(\Leftrightarrow x^2+2x+3=x+k\pi\)
\(\Leftrightarrow x^2+x+3-k\pi=0\)
\(\Delta=1-4\left(3-k\pi\right)\ge0\Leftrightarrow k\ge\frac{11}{4\pi}\Rightarrow k\ge1\)
Khi đó pt có nghiệm: \(\left[{}\begin{matrix}x=\frac{-1+\sqrt{4k\pi-11}}{2}\\x=\frac{-1-\sqrt{4k\pi-11}}{2}\end{matrix}\right.\) với \(k\ge1\)