a: \(\Leftrightarrow\left\{{}\begin{matrix}x>=-2\\x^2+4x+4-x^2+x-9=0\end{matrix}\right.\Leftrightarrow x=1\)
b: \(\Leftrightarrow\left\{{}\begin{matrix}x>=-1\\x^2+2x+1=x+13\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x>=-1\\x^2+x-12=0\end{matrix}\right.\)
=>x=3