题目

If you were asked to recite lines of poetry that have the Chinese character “hua”—which means flower—how many could you recite?He Liran, 13, had to tack on this challenge on a TV show aired by Shandong TV. He Liran, a student at the Harbin No 163 Middle School in Heilongjiang, competed with over 100 other students. The competitors took turns reciting lines of poetry that used the word “hua”, with He Liran replying to each one.One competitor used the line “As if the vernal breeze had come back over night; adorning thousands of pear trees with blossoms white.” He Liran replied wi 为了在夏季降温和冬季供暖时减少能源损耗，房屋的屋顶和外墙需要建造隔热层。某幢建筑物要建造可使用20年的隔热层，每厘米厚的隔热层建造成本为6万元。该建筑物每年的能源消耗费用C（单位：万元）与隔热层厚度x（单位：cm）满足关系：C（x）=若不建隔热层，每年能源消耗费用为8万元。设为隔热层建造费用与20年的能源消耗费用之和。     （1）求的值及的表达式。     （2）隔热层修建多厚时，总费用达到最小，并求最小值。