A math problem, difficult!! Who s going to help me

Isn't it 1704 kinds?,I'm not very good at math.,Especially permutations and combinations.,If there's any error.,Everyone points it out.,Thank you.。

Consider D first, which is divided into three scenarios:

D in the yellow. Consider a, e. Remove green and black, and arrange the remaining 4 colors in two colors. Considering the rest, there are 4 colors left to arrange. A total of 2a4·4a4=288 species.

D in green or black. Consider f, and then divide it into two more cases:

F put the remaining one of the green and black. There are 5 colors left to arrange. A total of 5a5=120 species.

f Put the other 4 colors that are not required. First of all, choose one of the four normal colors and put it in F. At this time, consider the remaining green and black ones.

This color can only be placed in B, C, and G, and choose one of these three pieces to put this color. Then consider the other 4 colors to arrange them. A total of 1c4·1c3·4a4=288 species.

d and put the other 4 colors. Considering f again, there are also two cases:

F put one between green and black. At this point, consider the remaining one. This color can only be placed in B, C, and G, and choose one of these three pieces to put this color. The other 4 colors are arranged. A total of 1c4·1c2·1c3·4a4=576 species.

F is one of the remaining 3 colors that are not required (because one was placed on D before). Both green and black can only be placed in b, c, and g. The remaining 3 colors are arranged. A total of 1c4·1c3·2a3·3a3=432 species.

It's a matter of permutations. If no conditions are attached.

Then there are 7*6*5*4*3*2*1 combinations = 5054 kinds, that is, A7, but the question restricts the conditions. Then there must not be so many.

Let's analyze: yellow can't put f green can't put ae black can't put ae we consider yellow can put f green a or e black put a or e several situations.

Yellow can put f 6a6 = 720

Green put a or e 2 * 6 a6 = 1420

Black put a or e 2 * 6a6 = 1420

All things considered: Is it 5054-720-1420-1420=1420?

If that's wrong.

Yellow can put f 6a6=720 without considering the case of green in a or in e, nor in the case of black in a or in e.

Then the excess must be added minus to. So how much less?

Similarly, there are also reductions in the other two cases. So how much to add.

I'm already confused. You guys want to put.

Method 1: Black and green, regardless of yellow, there are 5*4*5! = 2400 species, of which Huang Fang F has 4*3*4! = 288 kinds of inconsistencies, so there are 2400-288 = 2112 ways to put it.

Method 2: One of the black and green is placed in f to have 4*2! *5！= 960 kinds, none of which are placed in f in 4*3*4*4! = 1152, so there are 960 + 1152 = 2112 species.

There may be 5 * 4 = 20 kinds of green and black There may be 4 + 4 = 8 kinds of 1 in green and black There may be 4 + 4 = 8 kinds of 1, yes.

2. There are no 960 + 1536 = 2496 possibilities.

46 + 21 = 67.

Pick less is your more, and if you have 21 more, you can add 21.

67 pcs. Hope it helps.

Hello! Let's first calculate the cost of going out to Lotte Mart to buy iced tea:

30* yuan. 75/30=2...$15.

2*5=10 yuan.

75-10 = 65 yuan.

It costs 65 yuan to go to Lotte Mart supermarket.

It costs to go to Zhenda supermarket

Yuan) the amount of money needed to buy 6 bottles.

30 6 = 5 times.

5 yuan to Zhenda supermarket to spend yuan.

So it's cost-effective to go to Zhenda Supermarket.

Money needed for Lotte Mart:

30 bottles)...Buy 12 bottles and get 5 yuan back.

30 12 = 2 (times).6 (bottle) 30

65 (yuan) money required for Zhengda supermarket:

Meta)...The amount of money required to buy 5 + 1 = 6 bottles.

30 6=5 (times) 5 yuan) so it is cheaper to buy "iced tea" in Zhengda supermarket.

The class needs to buy 30 bottles.

Lotte Mart: It costs 75 yuan to buy 30 bottles, and 5 yuan for 30 slow bottles, which is equivalent to 65 yuan.

Zhenda Supermarket: You need to buy 25 bottles, plus 5 bottles back, a total of 30 bottles.

It costs 25* RMB.

So go to Zhenda supermarket.

30* yuan.

Rakuten: 75 30 = 2 2 * 5 = 10 75-10 = 65 (or: 30 back 5 can be seen as 2 bottles for every 12 bottles).

Zhenda: 30*5 (5+1)=25 person-times.

Less than 65

30 yuan can only return 2 30 yuan money).

Yuan (5 bottles back 1 bottle, 25 bottles back 5 bottles, 25 + 5 = 30 bottles) so choose Zhenda supermarket.

30 students.

Lotte Mart: $5 per bottle, $5 for every 30 yuan.

5 yuan for every 30 yuan and 10 yuan for 75 yuan.

Zhenda supermarket: yuan per bottle, 1 bottle for every 5 bottles.

1 bottle for every 5 bottles.

5 bottles for 25 bottles.

It's enough to buy 25 bottles.

Go to Zhenda Supermarket.

Lotte Mart: 30* yuan).

75-10 = 65 yuan.

Zhenda supermarket: 6 sticks = 5 sticks.

25* yuan).

Lotte Mart, spend 60 first, you can buy 24, and you can return 10 yuan to 4, that is, 60 yuan to buy 28, and then use 5 yuan to buy 2, a total of 65

Zhenda supermarket, buy 25 bottles first, use it, 5 bottles can be returned out of 25 bottles, you can buy 30 bottles.

Zhenda supermarket: yuan per bottle, 1 bottle for every 5 bottles. Yuan buys six bottles. There are 30 people in total, 30 6 = 5, 5*

Rakuten, $5 per bottle, $5 for every 30 yuan. 30 yuan can buy 30 bottles, a total of 30 people, need 2 30 yuan, that is, 28 bottles plus two bottles (5 yuan), that is, 65 yuan.

So Zhenda supermarket is cheaper.

Buy the iced tea in Zhenda supermarket, because it returns more money for the iced tea.

Solution: Lotte Mart: 2 5 30 75 (yuan).

75 2 5 65 (yuan).

Zhenda Supermarket: Buy 25 bottles.

25 2 5 62 5 (yuan).

Zhenda supermarket is cheap.

So choose Zhenda supermarket.

Buy it at Rakuten:,70-2x5=65 yuan.

To Zhenda buy: Yuan, so to Zhenda buy...

Rakuten is buy 12 and get 2 bottles free, which is equal to 6 to 1, while Zhenda is 5 to 1, which is obviously cost-effective.

ame= dmc=90- cme, mcd mae md=me i.e. mde is an isosceles right triangle.

s quadrilateral mecd=s cme+s cmd=s cme+s ame=s acm=s abc 2=4

1.Column equations.

Let the large single-line number be x, then the small single-line number is 4x, then the soft leather is (232-x-4x) to solve x2It took them 12-7-1 = 4 hours, 5 km on their descent and x hours on their ascent, 2x+5(4-x)=11

x = 3 hours.

So the uphill walked 2*3=6 km, and the descent walked 5*1=5km 3The length of the rope is 16x, and the depth of the well is y

The length of the rope that has been folded three times is 2x, and the length of the rope that has been folded four times is x, y=2x-2

y=x+1 gives x=3, y=4

Therefore, the length of the rope is 16*3=48 feet, and the depth of the well is 4 feet.

4.Cycling is 5 times faster than walking, and if the total distance is x, then 9x 10 has been walked by 9 minutes from home, and x 10 is left, and if x is walked for 50 minutes, it will take 10 minutes to walk x 10, so it will take at least 10 minutes.

1. Let the local number of the large single line be x, then the small single line is 4x

Solve x (is 4 times.

It's a very simple question. Let's go ask the teacher next.

1. 44 large books, 176 small ones, 12 soft ones, 2 copies

Well, I will do the third question: 7km up the hill and 5km down the mountain. If it's 12 p.m., it's a different story.

1.Let the big single line be * and find the relationship to be fun 2Eh, too lazy to type, too painful, happy, woo.

Question 3 converts complex numbers into exponential forms, and the answer is 0

In the sixth question, the complex number is expressed in exponential form, and according to the exponential operation, it is easy to conclude that argz represents the principal value of the radial angle of the complex number z.

Problem 5 is a first-order linear differential equation, first find the general solution of the corresponding homogeneous linear differential equation as y=cexp(-x 2 2), and then let c=c(x), that is, let y=c(x)exp(-x 2 2) is the general solution of the original equation, substitute the original equation, and find c(x)=x 3 3+c, so that the general solution of the original equation is y=(x 3 3+c)exp(-x 2 2).