2.把汽油以均匀的速度注入容积为60L的桶里.注入的时间和注入的油量如下表:
(1)求q与t的函数解析式.并判断q是否是t的正比例函数;
(2)求变量t的取值范围;
(3)求t=1.5,4.5时,q的对应值.
| 注入的时间(min) | 1 | 2 | 3 | 4 | 5 | 6 |
| 注入油量q(L) | 1.5 | 3 | 4.5 | 6 | 7.5 | 9 |
(2)求变量t的取值范围;
(3)求t=1.5,4.5时,q的对应值.
19.
如图,点A、B、C均在⊙O上,若∠ABC=40°,则∠AOC的大小是( )
| A. | 90° | B. | 80° | C. | 70° | D. | 50° |
18.方程x2=9的解是( )
| A. | x=9 | B. | x=±9 | C. | x=3 | D. | x=±3 |
17.一个正六边形的外接圆的半径为$\sqrt{2}$,则此正六边形的面积为( )
| A. | 3$\sqrt{3}$ | B. | $\frac{3\sqrt{3}}{2}$ | C. | $\frac{2\sqrt{2}}{3}$ | D. | 3$\sqrt{2}$ |
15.下列各组数值中,是方程2x-y=8的解的是( )
0 292007 292015 292021 292025 292031 292033 292037 292043 292045 292051 292057 292061 292063 292067 292073 292075 292081 292085 292087 292091 292093 292097 292099 292101 292102 292103 292105 292106 292107 292109 292111 292115 292117 292121 292123 292127 292133 292135 292141 292145 292147 292151 292157 292163 292165 292171 292175 292177 292183 292187 292193 292201 366461
| A. | $\left\{\begin{array}{l}{x=1}\\{y=-2}\end{array}\right.$ | B. | $\left\{\begin{array}{l}{x=2}\\{y=0}\end{array}\right.$ | C. | $\left\{\begin{array}{l}{x=0.5}\\{y=-7}\end{array}\right.$ | D. | $\left\{\begin{array}{l}{x=5}\\{y=-2}\end{array}\right.$ |