题目

Accounting is described as ________ science of classifying, recording and reporting ________ important financial events.        A. an, the       B. a, 不填      C. 不填, 不填      D. 不填, the 答案：B已知的展开式中第6项与第7项的系数之比为2：3，求n；若展开式的倒数第二项为112，求的值。(12分)