\(\left\{{}\begin{matrix}\widehat{A}+\widehat{B}=120^0\\3\widehat{B}-2\widehat{A}=10^0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}\widehat{A}=70^0\\\widehat{B}=50^0\end{matrix}\right.\)
=> ^C = 1800 - ^A - ^B = 600
Ta có ^A > ^C > ^B
=> BC > AB > AC

