Ejercicio 1
\[( x + 1 ) ( x - 2 ) = 0\]
\[x=\boxed{\phantom{\rule{2em}{1.2em}}}\]
Ejercicio 2
\[( x + 6 ) ( x + 1 ) = 0\]
\[x=\boxed{\phantom{\rule{2em}{1.2em}}}\]
Ejercicio 3
\[( x - 12 ) ( x - 5 ) = 0\]
\[x=\boxed{\phantom{\rule{2em}{1.2em}}}\]