Kẻ MH//KL//NO
\(\Rightarrow\widehat{LMH}=\widehat{MLK}=120^0\left(\text{so le trong}\right)\\ \widehat{NMH}+\widehat{MNO}=180^0\left(\text{trong cùng phía}\right)\\ \Rightarrow\widehat{NMH}=180^0-140^0=40^0\\ \Rightarrow x=\widehat{LMH}-\widehat{NMH}=80^0\)