\[8\frac{11^{\backslash 3}}{42} - 5\frac{43}{126} =\]
\[= 8\frac{33}{126} - 5\frac{43}{126} =\]
\[= 7\frac{159}{126} - 5\frac{43}{126} = 2\frac{116}{126} = 2\frac{58}{63}\]