Respuesta :

[tex]\underset{\leftarrow ~~ 6x+9 ~~ \to }{J\stackrel{20}{\rule[0.35em]{15em}{0.25pt}} K\stackrel{x + 9}{\rule[0.35em]{10em}{0.25pt}} L} \\\\\\ \stackrel{JL}{6x+9}~~ = ~~\stackrel{JK}{20}+(\stackrel{KL}{x+9})\implies 6x+9=29+x\implies 5x+9=29 \\\\\\ 5x=20\implies x=\cfrac{20}{5}\implies x=4\hspace{5em}\boxed{\underset{KL}{\stackrel{(4)~~ + ~~9}{13}}}[/tex]