题目

A few things to consider before booking a flight: With fuel costs rising and airlines finding more fees to impose on travelers every day, airfare isn’t getting any cheaper. Since you can’t drive to all your dream destinations, flying is the only way to go sometimes and, undeniably, the fastest. Luckily, there are plenty of ways to find the most affordable fares and also avoid paying as many extra charges as possible when you plan ahead. Getting the best fare Airlines put out their fare sales on Tuesday morning, making this day the best day to book a flight for less. Fly during the le若一次函数y=kx+b的图象沿y轴向上平移3个单位后，得到图象的关系式是y=2x+2，则原一次函数的关系式为 ．