题目

Given a square lawn with side length $a$ meters, now its north and south sides are increased by 3 meters and its east and west sides are each decreased by 3 meters. Is the area of the resulting rectangular lawn larger or smaller than that of the original one? How much is the diference? ——关联：代数式-整式、最值·差大积小🆗、结果与过程、平方差公式 ——链接：〚251003〛平方差应用✶✶💯

注：计算新面积，有2个思路