Function problems in the senior high school entrance examination in mathematics
The answers should be 2 and 4, not 2 and 3. A > 0。 When X= 1, y = c 0, you can get b < 0, so 2a-b > 0,3 is wrong; A > 0, b < 0, c < 0, so b * b+8a > 0, 4ac < 0, so b * b+8a > 4ac.