20 13 Chengdu senior high school entrance examination mathematics 28
(1) directly into A(0,-1)B((4,-1).
c =- 1； b=2。
(2) The vertex coordinates obtained from (1) are (2, 1) on the straight line AC (the function expression for finding AC), which is consistent. Therefore, I go to the picture when I have time, and it is rare to type on the keyboard.