下列各式从左到右的变形中，为因式分解的是（　　）

学校买来跳绳a根，每根跳绳6元，付出200元，应找回____元。

已知二次函数y=ax²+bx+c的图象如图所示，它与x轴的两个交点分别为（﹣1，0），（3，0）．对于下列命题：①2a+b=0；②abc<0；③b²-4ac>0；④8a+c＞0．其中正确的有 （   ）

Tick, tick, tick! Good morning, Jim! It’s 6:30 now. It’s time 1 up. Do you know me? I’m your new friend. My name is Clock. Look 2 me. I have no feet, 3 I can walk with my hands. I have no mouth, but I 4 speak to you. Now please listen to 5. Today is Monday. You have many things to do. Classes 6 at 8:00. You have four classes in the morning and two classes in the afternoon. After 3:40 you have a basketball match 7 Class Two. You come 8 at 5:40. You have supper at 6:00. You 9 CCTV news at 7:00. And you go to bed at 9:30. Now please get up quickly and have your breakfast or（否则）you will be 10.