\(\begin{array}{l}g'\left( x \right) = \dfrac{{\left( {2x - 2} \right)\left( {x - 1} \right) - \left( {{x^2} - 2x + 5} \right)}}{{{{\left( {x - 1} \right)}^2}}}\\g'\left( x \right) = \dfrac{{2{x^2} - 4x + 2 - {x^2} + 2x - 5}}{{{{\left( {x - 1} \right)}^2}}}\\g'\left( x \right) = \dfrac{{{x^2} - 2x - 3}}{{{{\left( {x - 1} \right)}^2}}}\\ \Rightarrow g'\left( 2 \right) = \dfrac{{{2^2} - 2.2 - 3}}{{{{\left( {2 - 1} \right)}^2}}} = - 3\end{array}\)
Chọn đáp án B.
