Unary inequality group calculation problem A little more, medium difficulty, easy is OK

-x 0, then x 2, 0, then xy 0;

3、|x-y|=y-x, is x y;

4. If. 5. If the value of the algebraic formula is less than 2, then the range of the value of x is

6. The positive integer solution of the inequality 3x 7<8 is

7. The corresponding points of the two real numbers A and B on the number line are shown in the figure below, fill in the blanks.

1）a___b； （2）|a|__b|；

3）a+b___0； （4）__0；

The following questions. 1) Y>0;(2) Y<0;

3) x, y=0;(4) x, y>4

2. Multiple choice questions (only one answer for each question).

1.If |a|-a, the value range of a is ( ).

a)a＞0; (b)a≥0; (c)a＜0;(d) Natural numbers.

2.The true of the following propositions is ( ).

a) If m≠n, then |m|≠|n|;b) If a+b=0, then ab 0;

c) If ab 0 and a b, then |a|＜|b|;

d) The product of two numbers of each other must be positive.

1. The length of a rectangular football field is xcm and the width is 70m, if its circumference is longer than 350m and the area is less than 7560m2, find the value range of x, and judge whether this field can be used as an international football match.

Note: The length of the football field used for international matches is between 100m and 110m and the width is between 64m and 75m).

2. There are 5 fewer rooms on the first floor of a hotel than on the second floor, and there are 48 people in a tour group, if all are arranged on the first floor, 4 people per room, the rooms are not enough, 5 people per room, and the rooms are not full; If you arrange to live on the second floor, each room for 3 people is not enough, 4 people per room, there are rooms that are not full, ask how many rooms are there on the first floor of the hotel?

3. A school is preparing to make a batch of commemorative albums for graduating students in companies A and B Company A proposed: 5 yuan for materials and 1,500 yuan for design fees; Company B proposed: 8 yuan per volume for materials, no design fee

1) Please write the functional relationship between the number of commemorative albums produced and the fees charged by Company A;

2) Please write the functional relationship between the number of commemorative albums to be produced and the fees charged by Company B;

3) If the school sends you to order a commemorative book from Company A and Company B, which company will you choose?

The problem of calculating a group of unary inequalities is shown in the following figure:

The trick of solving the unary one-dimensional inequality group method:The same is the big one:For example: x>-1;x>2；The solution set of the inequality group is x>2.

Take the small with the small:For example: x<-4;x<-6；The solution set for the inequality group is x<-6.

Find in the middle of the big and small:For example: x<2, x>1, the solution set of the inequality group is 1Big and small don't have to look for it:

For example: x<2, x>3, there is no solution for the inequality group.

If you look for it in the library, you will have many satisfactory answers.