Urgently needed 6th grade Optimized Learning 40 days of answers 20

You might as well find a classmate to copy it before the start of school, otherwise no one will patiently send it to you when your question is closed.

Otherwise, you can write well, which will help you in your studies.

The two sides of the inequality mx greater than 2 are multiplied by one-part of m to obtain that x is less than 2/2 of m, and the range of values of m is obtained.

Because of the change of number, m<0

2.A school held an interest group on Tuesday, which was divided into three categories: science and technology, humanities, and fitness, and the ratio of the number of the three was 9:4

5. First transfer from science and technology to humanities 2x people, from science and technology to fitness x people, so that the number of people in the three courses is equal, the total number of students in the school is between 170 185, ask how much x? (To have a process, thanks pull!) ~）

Let the proportionality factor be k

9k-3x=4k+2x5k=5xx=k, so k is an integer (because it is equal to the number of people who are transferred).

170<=9k+4k+5k<=185

170<=18k<=185 k=10 so x=10

3.The fast train travels 60 kilometers per hour, the slow train travels 48 kilometers per hour, and the two cars depart from the two stations A and B at the same time, which are 124 kilometers apart, and go in opposite directions, asking how many hours later the two cars are 240 kilometers apart? (To have a process, thanks pull!) ~）

Set the time to x60+48)x+124=240

x = (240-124) 108 = 29 27 (hours).

4.Xiaojie and Xiaoli practiced running and race walking on the 400-meter circular track respectively, the ratio of Xiaojie's speed to Xiaoli's speed was 8:3, the two started from the same direction at the same time, met 2 minutes later, and asked Xiaojie's speed what? （

Let Xiaojie's speed be x Xiaoli's speed and 3x 8

When they met, Xiao Jie walked 400 meters more than Xiao Li.

2x=400+2x3/8x

5/4x=400

x = 320 (mm).

You didn't even say what grade you were in? ~

You'll have to find it yourself

From -2< 1 2x-1< 1, we get -1<1 2x<2 (add 1 to both sides of the inequality).

Further there is -2-2, so x+2>0, then 2(x+2)>0, i.e. 2x+4>0

This means that 2x+4 is a positive number, hence |2x+4|=2x+4；

On the other hand, x<4, so x-4<0, which means that x-4 is negative, hence |x-4|=4-x。

So |2x+4|-|x-4|=2x+4-(4-x)=3x

-2<1 2x-1<1 gives -1<1 2x<2, and continues to solve -2 so -4<2x<8,0<2x+4<12,-62x+4-(4-x)=3x

Solution: -2< 1 2x-1< 1

The absolute value of -2 2x+4 is positive.

The absolute value of x-4 is negative.

The absolute value of 2x+4 is equal to 2x+4

The absolute value of x-4 is equal to 4-x

Original = (2x+4)-(4-x).

2x+4-4+x=3x

Known -2< 1 2x-1< 1

2< x< 4, 0<2x+4, directly remove the absolute value symbol x-4< 0 becomes 4-x, and then remove the absolute value symbol.

The end result is 3x

On the first day, the first four are correct and the last one is wrong, fill in the blanks in question 6, 96,34 (even), odd 19,23,65,27, prime 19,23, composite 96,34,27,65, zero in the seventh question, 1 positive integer number, and 8th question 1,2,3,6,9,18

16 days: 1. Judge right and wrong.

Second, fill in the blanks. 5, c = d or 2 r

6, 3 times, 3 times.

7,2 cm.

8,16 dm.

Three, choice. 9，c10，b

11，b12，b

Fourth, the answer. 13, the same.

14, m. 15,157 trees.

16,10 minutes.

17, cm.

18,317 centimeters decimeter.

19, m. 20, walk more meters, walk more meters, walk more meters.

I hope the task will be accepted, thank you.