Đáp án:
1)
$\dfrac{6039}{7}\\
2)
\widehat{xOt}=75^{\circ}$
Giải thích các bước giải:
1)
$19\dfrac{5}{8}:\dfrac{7}{2013}-26\dfrac{5}{8}:\dfrac{7}{2013}\\
=\left ( 19\dfrac{5}{8}-16\dfrac{5}{8} \right ):\dfrac{7}{2013}\\
=\left ( 19-16+\dfrac{5}{8}-\dfrac{5}{8} \right ):\dfrac{7}{2013}\\
=3.\dfrac{2013}{7}\\
=\dfrac{6039}{7}\\
2)
\widehat{yOz}=\widehat{xOy}-\widehat{xOz}=110^{\circ}-40^{\circ}=70^{\circ}$
Vì Ot là tia phân giác của góc $\widehat{yOz}$
nên $\widehat{yOt}=\widehat{tOz}=35^{\circ}$
$\widehat{xOt}=\widehat{xOz}+\widehat{zOt}=40^{\circ}+35^{\circ}=75^{\circ}$