Math problems, which require you to write down the equation and the answer. 20 points are given afte

x=-5x=5

2.There are x pcs.

x-20）/30=（x+10）/35

35x-700=30x+300

5x=1000

x=200 (pcs).

There are 36 distances between the 37 poles.

Each section is 50 meters, a total of 1,800 meters.

Now change each section of 50 meters to 60 meters, only require 50 and 60 two numbers within less than 1800 common multiple numbers, respectively, 300, 600, 900, 1200, 1500, so in addition to two ends, there are 5 telephone poles in the middle do not need to move.

This question is the same as the previous question, only need to pay attention to the change of the total range, the original 26 flags accounted for a total distance of (26-1)*4=100 meters, now changed to 25*5=125 meters, which is wider than the original distance.

Therefore, the number of common multiples of 4 and 5 within 100 is required, respectively: 20, 40, 60, 80, 100, a total of 5.

That is, in addition to the first one, there are 5 flags that do not need to be moved.

1：4x-5x=-3-2

x=-5x=5

2: Set up x boxes, there are Y apples in total.

30x+20=y

35x-10=y

Simultaneous two equations:

30x+20=35x-10

5x=30x=6

y=6*30+20=200 (pcs).

+3=5x-4x x=5

2. If there are x fruits, then (x-20) 30=(x+10) 35 x=200

3. The total length of the road is (37-1) * 50 = 1800 meters, and 50 meters is changed to 60 meters, then every 300 meters remains unchanged, and 1800 300 = 6

It includes 6+1=7 poles at the starting point of every 300 meters, and 7-2=5 at both ends.

4. The road length is (26-1) * 4 = 100 meters, and if 4 meters is changed to 5 meters, then every 20 meters will not change, 100 20 = 5, and the starting point will not change, that is, there will be a total of 5 + 1 = 6 roots that do not move.

x-4x=3+2

x=52.Solution: 30 per box is 20 more, 35 per box is 10 less.

The second way to put and the first comparison, when each box put 5 more, not only the original extra 20 put out, but also can put 10 more apples, it can be seen that the second way to put and the first comparison, when each box put 5 more, a total of 20 10 = 30 more.

From this, the number of boxes can be calculated: (20 10) (35 30) 6 (boxes) Number of fruits: 30 6 20 200 (pieces) 3

The positions that can be divisible at the same time, a total of 36 50 300 = 12 points, minus the end point does not need to move, a total of 11 points do not need to move.

These three sides, multiples of 4 and 5.

20 15 Did the water rise in meters or centimeters? )

1. Tile area: 1080m2 Water volume: 1875m3

2. Iron volume:

Since the average weight of A and B is 8 kg less than the average weight of A and C, it can be seen that B is 16 kg lighter than C, and the average weight of B and C is 49 kg or more: B + (B + 16) = 49 * 2, then B = 41 (kg); C = 57 (kg).

From the average weight of B and D is heavier than the average weight of A and C: 41 + D 57 + A, and D - A 16, that is, D is more than 16 kg heavier than A.

Because the average weight of two of them is equal to the average weight of the other two, because.

D + C (heavy + heavy) cannot be equal.

A + B (light + light);

That can only be. D + A = B + C = 49 * 2 (kg).

(1) The point between DF is called G

de=6 >>be=6>>>ec=2>>>cf=4>>>cg=4 s=(6+4)*2/2=10

104 4=26>>>ae=26-17=9 One triangle has an area of 9*17 2 Four triangles have an area of 4*9*17 2=306

The whole ABCD area is 26*26=676, so the EFGH area is 676-306=370

Give points.

Let's set the total work to be 1, then according to the first sentence:

A does eight hours a day and can do it for 30 consecutive days, B does ten hours a day and does it for 22 consecutive days" can be obtained: A does 1 240 per hour, B does 1 220 per hour.

Pay attention to the second sentence: "A has to take a day off every six days, and B has to take a day off every five days", look down, now A and B cooperate, do eight hours a day, do thirteen days, stop!

Up to now (i.e. the 13th day), A has worked 12 days and B has worked 11 days, each for 8 hours each. So, now they have done a total of 1 240 * 8 * 12 + 1 220 * 8 * 11 = 4 5

So, now the remaining 1 5 will be made by A.

Let's calculate that A does 6 hours a day, and the total amount of work to do is 1 5 (1 240*6) = 8 days.

Note! A has to take a day off for 6 days, so the 8 days of work, A took 8+1=9 days to complete!

So it took 13 + 9 = 22 days to complete this work.

Let the whole job be W

Then A's efficiency per hour is w 240, and B is w 220, and A does n days later (excluding rest).

In the first 13 days, A did 12 days and B did 11 days, and the equation was:

w 240 * 8 * 12 + w 220 * 8 * 11 + w 240 * 6 * n = w solve the equation to get n = 8

So it took 13 + 8 + 1 = 22 days to complete this work.

Since I typed it out in word、、There are some symbols in it that cannot be displayed after uploading。 So I'll take a screenshot for you.

The absolute value of the original formula = (47 8 + 5 4) is: 57 857 8-45 The absolute value of 8 is: 12 8 = 3 2 The original formula = -9-3-|-8+6|

Whew I'm tired to death, I finally typed it, I hope it helps you!

1.The area of the shadow is equal to the area of the rectangle minus the area of the triangle AFC minus the area of the triangle DBF plus the area of EFGH.

And the sum of the bases of these two triangles is the length of BC, and the height is the same height AB, so S Yin = BC * AB 2 + 36 = 12 * 20 2 + 36 = 156 (square centimeters).

2.The area of the quadrilateral ABCD = 16 * 20 = 320 (square centimeters), the area of the triangle DMC = 16 * 10 2 = 80 (square centimeters), the area of the triangle APD = 320-120-80 = 120 (square centimeters), AP = 120 * 2 20 = 12 (centimeters).

pb = 16-12 = 4 (cm).

Area of triangle PBM = 4 * 10 2 = 20 (square centimeters) Area of triangle PMD = 120-20 = 100 (square centimeters).

Cm.

120-36 = 84 square centimeters.

s shade = 12x20-84 = 156 square centimeters.

2.Solution: If there are x chests, there will be (30x+20) fruits.

35x-10=30x+20

x=6A: There are 200 fruits.

3.50*（37-1）=1800m

1800 300 = 6 (root) Answer: 6 root.

100 20 = 5 sides.

Answer: 5 sides.

2.30 per box is 20 more (30 per box is 10 less).

The least common multiple of 30 and 35 is 210, so at least 200 fruits.

3.Every 300 meters there is one that does not move, so there can be 7 that do not move (including the head and tail), so there are 5 that do not move.

4.Ditto. But the tail doesn't count. So there are 5 that don't need to be moved.