a: \(\widehat{xOm}+\widehat{yOm}=180^0\)(hai góc kề bù)
=>\(\widehat{yOm}+80^0=180^0\)
=>\(\widehat{yOm}=100^0\)
b: On là phân giác của góc mOy
=>\(\widehat{mOn}=\widehat{yOn}=\dfrac{\widehat{mOy}}{2}=50^0\)
c: Ta có: \(\widehat{xOn}+\widehat{yOn}=180^0\)(hai góc kề bù)
=>\(\widehat{xOn}+50^0=180^0\)
=>\(\widehat{xOn}=130^0\)