圖片參考:http://imgcld.yimg.com/8/n/HA04937267/o/701204150034213873394380.jpg
thx.
更新1:
第1題點factorize? 第2題=.=我唔係好明,sorry 可以解釋一下嗎?thx
更新2:
ok...anyway thx.. Although i thought they are very difficult= =..