一个小皮球重45克，一个大皮球重54克，一个大皮球和一个小皮球总重为____.

增加：在缺词处加一个漏字符号（∧），并在其下面写出该加的词。

删除：把多余的词用斜线（\）划掉。

修改：在错的词下划一横线，并在该词下面写出修改后的词。

注意：1）每处错误及其修改均仅限一词；

2）只允许修改10处，多者（从第11处起）不计分。

    I'm a huge book-lover but like sharing my love for books! So I've been bought books constantly. Finishing reading one book, I placed it in or around my school so that some of my schoolmate can enjoy themselves when reading it. I especial like placing it on a stone table in the little garden in that students might have time to take a rest. I was delighted an other day when I saw a card left on the table to say thanks. And from the card, I knew my book turned out of to be a birthday gift for a strange girl. It was so lovely find out that my book could bring anyone pleasure!

已知△ABC的两个顶点A，B的坐标分别为（﹣2，0），（2，0），且AC，BC所在直线的斜率之积等于﹣$\frac{1}{4}$．

（1）求顶点C的轨迹方程；

（Ⅱ）若斜率为1的直线l与顶点C的轨迹交于M，N两点，且|MN|=$\frac{8\sqrt{2}}{5}$，求直线l的方程．