\(\left(x+1\right)\left(x+4\right)=\left(2-x\right)\left(x+2\right)\)
\(\Leftrightarrow x^2+5x+4+\left(x-2\right)\left(x+2\right)=0\)
\(\Leftrightarrow x^2+5x+4+x^2-4=0\)
\(\Leftrightarrow2x^2+5x=0\)
\(\Leftrightarrow x\left(2x+5\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-\frac{5}{2}\end{matrix}\right.\)