а) \(\frac{11}{12}\cdot\frac{24}{7}:\frac{32}{21}-\left(\frac{19}{6}-\frac{37}{15}\right):\frac{7}{5}=\frac{33}{32}-\frac{7}{18}=\frac{17}{288}\).
б) \(51-(86,45:24,7+1,25)\cdot2,4-36,99=51-(3,5+1,25)\cdot2,4-36,99=51-11,4-36,99=2,61\).
Так как \(\frac{17}{288}\approx0,059\), то \(\frac{17}{288}<2,61\).
Ответ: \(\frac{17}{288}<2,61\).