3. 如图,直线$AB$对应的函数表达式是 (

A. $y = -\frac{3}{2}x + 3$
B. $y = \frac{3}{2}x + 3$
C. $y = -\frac{2}{3}x + 3$
D. $y = \frac{2}{3}x + 3$
A
)A. $y = -\frac{3}{2}x + 3$
B. $y = \frac{3}{2}x + 3$
C. $y = -\frac{2}{3}x + 3$
D. $y = \frac{2}{3}x + 3$
答案
A
4. 在$y = kx + b(k≠0)$中,若$x = 1$时,$y = 2$,$x = 2$时,$y = 1$,则当$x = 3$时,$y = $ (
A. $-2$
B. $1$
C. $3$
D. $0$
D
)A. $-2$
B. $1$
C. $3$
D. $0$
答案
D
5. 已知$y$是$x$的一次函数,下表中列出了部分对应值,则$m$等于 (
| $x$ | $-1$ | $0$ | $1$ |
| --- | --- | --- | --- |
| $y$ | $1$ | $m$ | $-1$ |
A. $-1$
B. $0$
C. $\frac{1}{2}$
D. $2$
B
)| $x$ | $-1$ | $0$ | $1$ |
| --- | --- | --- | --- |
| $y$ | $1$ | $m$ | $-1$ |
A. $-1$
B. $0$
C. $\frac{1}{2}$
D. $2$
答案
B
6. 直线$y = ax + b(a≠0)$过点$A(0,1)$,$B(2,0)$,则关于$x$的方程$ax + b = 0$的解为 (
A. $x = 0$
B. $x = 1$
C. $x = 2$
D. $x = 3$
C
)A. $x = 0$
B. $x = 1$
C. $x = 2$
D. $x = 3$
答案
C
7. 如图,直线$y = ax - b$与直线$y = mx + 1$交于点$A(2,3)$,则关于$x$,$y$的方程组$\begin{cases}ax - y = b,\\mx - y = -1\end{cases}$的解为 (

A. $\begin{cases}x = 2,\\y = 3\end{cases}$
B. $\begin{cases}x = 3,\\y = 2\end{cases}$
C. $\begin{cases}x = -3,\\y = -2\end{cases}$
D. $\begin{cases}x = -2,\\y = -3\end{cases}$
A
)A. $\begin{cases}x = 2,\\y = 3\end{cases}$
B. $\begin{cases}x = 3,\\y = 2\end{cases}$
C. $\begin{cases}x = -3,\\y = -2\end{cases}$
D. $\begin{cases}x = -2,\\y = -3\end{cases}$
答案
A
8. 数形结合是解决数学问题常用的思想方法.如图,一次函数$y = kx + b(k,b$为常数,且$k < 0)$的图象与直线$y = \frac{1}{3}x$都经过点$A(3,1)$,当$kx + b < \frac{1}{3}x$时,根据图象可知,$x$的取值范围是 (

A. $x > 3$
B. $x < 3$
C. $x < 1$
D. $x > 1$
A
)A. $x > 3$
B. $x < 3$
C. $x < 1$
D. $x > 1$
答案
A
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