《2025年暑假作业河北美术出版社七年级数学人教版》

1. 下列是一元一次不等式组的是 (A)

A.$\left\{\begin{array}{l} x＞-2,\\ x＜3\end{array} \right.$
B.$\left\{\begin{array}{l} x+1＞0,\\ y-2＜0\end{array} \right.$
C.$\left\{\begin{array}{l} 3x-2＞0,\\ (x-2)(x+3)＞0\end{array} \right.$
D.$\left\{\begin{array}{l} 3x-2＞0,\\ x+1＞\frac {1}{x}\end{array} \right.$

答案： 1. A

2. 不等式组$\left\{\begin{array}{l} 2x-1≥x+1,\\ x+8≤4x-1\end{array} \right.$的解集是 (A)

A.$x≥3$
B.$x≥2$
C.$2≤x≤3$
D.无解

答案： 2. A

3. 若关于$x的不等式组\left\{\begin{array}{l} x-a＞0,\\ 1-2x＞x-2\end{array} \right.$无解,则$a$的取值范围是 (A)

A.$a≥1$
B.$a＞1$
C.$a≤-1$
D.$a＜-1$

答案： 3. A

4. 已知关于$x的不等式组\left\{\begin{array}{l} x＞a,\\ x＞b,\end{array} \right. 数轴上表示a,b$的点如图所示,则这个不等式组的解集为____x ＞ a.

答案： 4. $ x ＞ a $

5. 若关于$x,y的方程组\left\{\begin{array}{l} 2x+y= 3k-1,\\ x+2y= -2\end{array} \right. 的解满足\left\{\begin{array}{l} x+y＞1,\\ x-y＞5,\end{array} \right. 则k$的取值范围是____k ＞ 2.

答案： 5. $ k ＞ 2 $

6. 若关于$x的不等式组\left\{\begin{array}{l} \frac {4+x}{3}＞\frac {x+2}{2},\\ \frac {x+a}{2}＜0\end{array} \right. 的解集为x＜2$,则$a$的取值范围是____a \leq -2.

答案： 6. $ a \leq -2 $

7. 解下列不等式组:
(1)$\left\{\begin{array}{l} 5x-1＞2x+5,\\ x-4＜3x+1;\end{array} \right. $
(2)$\left\{\begin{array}{l} x-2＜1,\\ 4x+5＞x+2;\end{array} \right. $
(3)$\left\{\begin{array}{l} 2x+3≥x+11,\\ \frac {2x+5}{3}-1＜2-x;\end{array} \right. $
(4)$\left\{\begin{array}{l} 2(x+1)＞5x-7,\\ \frac {x+10}{3}＞2x.\end{array} \right. $

答案： 7.
(1) $ x ＞ 2 $.
(2) $ -1 ＜ x ＜ 3 $.
(3) 无解.
(4) $ x ＜ 2 $.