题目

Jenny gets up early in the morning. She has her breakfast and then goes to school. She walks to the bus stop and takes a bus. She gets to school at about half past seven. Jenny is never late for school. She likes her school and works hard. Classes begin at 8:00. She has six classes every day. Jenny is good at all her lessons, and she likes English best.Usually Jenny has lunch at school. She goes home at five in the afternoon. Sometimes, she helps her friends with their lessons. After supper she usually watches TV news. Then she does her homework. She goes to bed at about 9:30. Jenny is已知函数f（x）=ax3+bx2，f（x）在点（3，f（3））处的切线方程为12x+2y-27=0．（Ⅰ）求函数f（x）的解析式；（Ⅱ）若对任意的x∈[1，+∞），f′（x）≤klnx恒成立，求实数k的取值范围．