Đạo hàm của hàm số

\[\begin{array}{*{20}{l}}{y' = \frac{{{{\left( {ax + b} \right)}^\prime }\left( {cx + d} \right) - \left( {ax + b} \right){{\left( {cx + d} \right)}^\prime }}}{{{{\left( {cx + d} \right)}^2}}} = \frac{{a\left( {cx + d} \right) - c\left( {ax + b} \right)}}{{{{\left( {cx + d} \right)}^2}}}}\\{ = \frac{{acx + ad - acx - bc}}{{{{\left( {cx + d} \right)}^2}}} = \frac{{ad - bc}}{{{{\left( {cx + d} \right)}^2}}}}\end{array}\]