Đề bài

Cho hàm số \(f\left( x \right) = \frac{1}{{2x + 3}}.\) Khi đó, \(f'\left( x \right)\) bằng:

A. \( - \frac{1}{{{{\left( {2x + 3} \right)}^2}}}.\)

B. \( - \frac{2}{{{{\left( {2x + 3} \right)}^2}}}.\)

C. \(\frac{2}{{{{\left( {2x + 3} \right)}^2}}}.\)

D. \(\frac{1}{{{{\left( {2x + 3} \right)}^2}}}.\)