Ask for the second question 2 The third question 1 2 , the first year of mathematics, thank you

Solution: Set the water use xm3 in March.

2x+2 6+4 4+8(15 x 10)=44 solution: x=4 6,15 4=11m3

2x+12+4（15﹣x﹣6）=44

When the water consumption in March exceeds 6m3

, but not more than 10m3

, if the water consumption is xm in March, it will exceed 6m3 in April

, but not more than 10m3

When: no solution (abandonment).

So in March 4m3 of water was used

In April, 11 m3 of water was used

Solution: (1) There are X people in the seventh grade and Y people in the eighth grade.

First of all, because when purchasing tickets separately, the ticket price paid by the seventh grade is 15 yuan for the person and the ticket price paid by the eighth grade is 12 yuan.

15 * x + = 1575, i.e. x + = 105x + y > x + 105, so the total number of people is more than 100 people.

Since the total number of people is more than 100 people, the ticket ** is 9 yuan, and the ticket purchase together needs to pay 1080 yuan, there is x + y = 1080 9 = 120, that is, the total number of people is 120 people.

2), = 15, i.e. y = 75, x = 120 - 75 = 45 (people).

There are 45 students in the seventh grade and 75 students in the eighth grade.

I wish you progress in your studies, and hopefully.

Set up x people in the seventh grade, y people in the eighth grade, as known by the question, x is less than 50, y is greater than 50 less than 100, and 15x+15

Assuming x+y is greater than 100, then.

Calculate the equation to get x,y, then verify whether x is less than 50, y is greater than 50 less than 100, and then assume that x+y is less than 100, then.

Calculate x,y to verify whether x is less than 50 and y is greater than 50 and less than 100, and verify that it meets the correct answer.

1: Let the speed of B be x, and the speed of 12* will be 16 km/h.

2: Let the machine be x x 4-((2 3)x) 4-((1 3)x) (4* The total number of machines is: 36 is planned to be 36 4, that is, 9 days to complete.

1.Solution: Let the velocity of B be x, then the equation can be columned:

x+12)*(6/60)=

The solution is x=16km h

2.Solution: If there are x sets of machines and are planned to be completed in y days, then the system of equations can be listed:

4*y*(1-2/3)= *x /4)-1) -1)4y=x---2)

Solution: x=36, y=9

1.Solution: Let the velocity of B be x, and the equation according to the meaning of the problem is obtained:

12+x）*（6/60）=

Solution: x=16

2.Solution: The original plan was planned to be completed in x days, according to the title:

x-[(2 3) (1 x)+(1 3) (solution: x=9.)

The machine has: 4x=4*9=36

1.Let B's velocity be x, then (12+x)*, and the solution is x=16 km/h2If there are always x machines, then x 4 = 1 + 2 x 12 + x 18, and the solution is x = 36 sets, which was originally planned to take 9 days.

1.Solution: Let the velocity of B be xkm h

From the title: 12x(6 60)+6 60x=

Solution: x=

There are 3 types of simple parts, which are 2 4 8, 4 8 16, 5 10 20. Then find out how much each cost, and you will know the answer if you meet the requirements.

Question 1: Root number 36 is less than root number 40 is less than root number 49

So 6 is less than the root number 40 and less than 7

So a+b=6+7=13

Question 2: The square of 5 is equal to 25, and the root number 25 is less than the root number 26, so 5 is less than the root number 26 and the root number 2 is approximately equal to, so that the root number 2 is greater than.

The root number five is approximately equal to it, so it is less than 1 minus one

6^2=36

36<40<49, so a=6,b=7,a+b=135= 25, 25< 26, so 5< 26 2 is approximately equal to, so 2>

5 is approximately equal to >1, so 5-1>1

The second question, 9, cannot be 4 because the sum of the two sides is greater than the third side

The third question can be 11, as long as the sum of the two sides is greater than the third side, and the difference between the two sides is less than the third side.

The other side must be 9cm

Because it is a waist triangle, if two sides are 4cm and one is 9cm, the other side cannot form a triangle, and the other side must be "6!".

Because the sum of the two sides of a triangle must be greater than the other!

1, b and.

2. Positive: cycle) 2 12 13 Negative: -1 7 -2 3

Rational numbers: -1 7 cycles) 12 13 -2 3 irrational numbers: 2