I'm Lisa. My father is a doctor. He often drives his car to work. My mother is an English teacher. She always walks to work. She says walking is a good way to exercise. My mother also likes going shopping. She often does some shopping on Sundays. I am a student. I usually ride a bike to school, but sometimes I come to school by bus. I like watching TV. I only watch TV on Saturday and Sunday evenings.

东门天虹商场购进一批“童乐”牌玩具，每件成本价30元，每件玩具销售单价x（元）与每天的销售量y（件）的关系如下表：

若每天的销售量y（件）是销售单价x（元）的一次函数

（1）求y与x的函数关系式；

（2）设东门天虹商场销售“童乐”牌儿童玩具每天获得的利润为w（元），当销售单价x为何值时，每天可获得最大利润？此时最大利润是多少？

（3）若东门天虹商场销售“童乐”牌玩具每天获得的利润最多不超过15000元，最低不低于12000元，那么商场该如何确定“童乐”牌玩具的销售单价的波动范围？请你直接给出销售单价x的范围．

函数f（x）=x³﹣3x﹣1，若对于区间﹣3，2上的任意x₁，x₂都有|f（x₁）﹣f（x₂）|≤t，则实数t的最小值是（　　）