It's easy for you ① The purchase price of a certain T-shirt is 400 yuan, and the price is 600 yuan when it is sold. Due to the change of season, the store is ready to sell it at a discount, but how much discount is it to keep the profit no less than 5%? ② The total cost of two pieces of clothing is 500 yuan. In order to make a profit, the store owner decides to price the clothing at 50% of the profit and the clothing at 40% of the profit. When the clothing is actually sold, at the customer's request, the two pieces of clothing are sold at a 10% discount. In this way, the store owner makes a total profit of 157 yuan. How much is the cost of the two pieces of clothing

1. Set a discount of X,
600*X=400*(1+5%)
X=0.7
70% off
2. If the cost of Party A is x yuan, then the cost of Party B is 500-x yuan
X*1.5*0.9+(500-X)*1.4*0.9=500+157
1.35X+630-1.26X=657
0.09X=27
X=300
500-300=200
The cost of a is 300 yuan and that of B is 200 yuan

1. A worker installs a batch of machines. If four machines are installed every day, it is expected to be completed in several days. After two thirds of the machines are installed, the new method is used to install them. The work efficiency is increased to three thirds of the original. Therefore, the machines are completed one day ahead of the expected time. How many machines are there?
2. There are three water pipes (a, B and C). When a pipe is opened alone, a pool of water can be filled in 5 hours. When a pipe and B pipe are opened together, a pool of water can be filled in 2 hours. When a pipe and C pipe are opened together, a pool of water can be filled in 3 hours?

The machine has X
x/4-(2x/3÷4+x/3÷6)=1
Time together x
(1/5+3/10+2/15)x+2(3/10+2/15)=1

A batch of TV sets in a store, originally priced at 2500 yuan, are now sold at a 20% discount. If you want to make the monthly sales before and after the price reduction reach 100000 yuan, how many sets should be added to the monthly sales?

Suppose that the monthly sales volume should be increased by X units. According to the meaning of the question, we can get the following result: x = 10

A: 40 ° W, 20 ° e, 40 ° n, 40 ° s
Q: where is a in the five belts? Where is B in the five belts? Do a and B have direct sunlight? Do a and B have polar day and polar night?

There is something wrong with your question. The longitude and latitude coordinates of a place must be one longitude and one latitude. How can two longitudes or two longitudes appear at the same time? Please make sure the correct position coordinates of two points AB, otherwise you can't answer

Is it right or wrong that the common factor of all nonzero natural numbers is 1

That's right, because as long as any natural number is non-zero, its common factor is 1

If the equation 4 ^ x + A2 ^ x + A + 1 = 0 about X has a solution, then the value range of real number a is
I'm very ambivalent about this question. Please help me. Thank you
Then please describe the process in detail.

Let 2 ^ x = y
Then the original equation is
y^2+ay+a+1=0
If x has a real solution, then y also has a real solution
∴△≥0
∴a^2-4(a+1)≥0
The solution is 2-radical 8 ≥ a or a ≥ 2 + radical 8
At the same time, Y > 0
Then (- A + - radical (△)) / 2 > 0
Solving inequality

What is the simplest integer ratio of 1.5:0.4?

The simplest ratio of 1.5:0.4 is 15:4 and the ratio is 3.75

What is (- 1) + 2 + (- 3) + 4 +... + (- 99) + 100?

(-1)+2+(-3)+4+...+(-99)+100
=(2-1)+(4-3)+...+(100-99)
=50*1
=50

The function f (x) = (12) X-1 such that f (x) is an increasing function and the interval of X is______ ．

Since the function f (x) = (12) X-1 = (12) X-1 & nbsp;, & nbsp; X ≥ 1 (12) 1-x, & nbsp; x < 1, as shown in the figure, the increasing interval of the function can be obtained by combining numbers with shapes as (- ∞, 1], so the answer is (- ∞, 1]

How many Mu is one square kilometer?

One mu is equal to 666.67 square meters
1 square kilometer = 1 kilometer * 1 kilometer = 1000 meters * 1000 meters
= 1000000 square meters = 1499.993 Mu