| A | x>1 |
| B | x≥1 |
| C | x>-2 |
| D | x≥-2 |
函数y=
中,自变量x的取值范围是( )
| A | x≥1且x≠3 |
| B | x≥1 |
| C | x≠3 |
| D | x>1且x≠3 |
| A | S=120-30t(0≤t≤4) |
| B | S=120-30t(t>0) |
| C | S=30t(0≤t≤40) |
| D | S=30t(t<4) |
| A | (1)和(2) |
| B | (1)和(3) |
| C | (2)和(4) |
| D | (1)和(4) |
| A | y=24-2x;0<x<6 |
| B | y=24-2x;0<x<4 |
| C | y=24-3x;0<x<6 |
| D | y=24-3x;0<x<4 |