When it comes to math questions, it won t be too difficult

The first equation is 2x+y=25

Didn't you make it ...

You... Solution: Set the waist length x and the bottom length y

2x+y=25

x+x/2):(y+x/2)=3:2

x=10,y=5

You got the first equation wrong.

There are 2 solutions.

The first equation is 2x+y=25

There should be 2 of them in the second formula.

x+x/2):(y+x/2)=3:2

x+x/2):(y+x/2)=2:3

This solves that y is 5 and 10.

Set the waist length x and the bottom length y

The midline of a waist passes through the midpoint of the waist Divides the whole large triangle into two small triangles, and the circumference ratio mentioned in the title is the ratio of the length of the midline by removing the circumference of the two small triangles.

The original circumference was 2x+y=25

Now split into two small triangles.

The ratio of x+x 2 : y+x 2 =3 : 2 gives x=2y and because 2x+y=25

So 5y=25y=5 x=2y=10

Solution: Set the waist length x and the bottom length y

2x+y=25 ①

x+x/2):(y+x/2)=3:2 ②

3x-3x/2=3y

3x/2=3y

x=2ySubstituting x=2y into :

4y+y=25

y=5x=2y=10

A: The bottom edge of this triangle is 5 cm long.

If the number of single digits is 2x, then the number of 19 digits is 10x

The number z can be expressed as 10x+2x

If you swap the number in the single digit with the number in the ten digit.

This number is expressed as 20x+x

then (20x+x)-(10x+2x)=36

21x-12x=36

9x=36x=4

After bringing it in, it came to be 48

The number on the single digit is 2 times the number on the ten digit, indicating that the number on the single digit is an even number, if the single digit is exchanged with the number on the ten digit, the new number obtained is 36 larger than the original number, that is, even number - a number = even number, indicating that the number on the ten digit is also an even number, and only 4 can be taken

The single digit is 2*4=8

This number is 48

The second one seems to be a bit problematic.

If the second is.

The solution of 1/x-1/x-1 = 1/3 of x-1 - 1/1 of x-4 is x=2, and the solution of x-n + 1/2 - x-n + 1/1 = x-n - 1/1 of x-n - 1/2 is x=n

Observe the second one, substituting x=y+1, it becomes the first formula, but x is replaced by y, and x=y+2 is substituted, and the third one is the same.

Then, if the solution is x=n, then let x=y+n-1, we get.

The solution of y+1/1 - 1/y = y-1/2 - y-1/3 is y=1, and y=x+1-n, and the conclusion is obtained by substitution.

Validation, since y=1, x=n, satisfies.

If the second one of your questions is not wrong, I don't say it.

The solution of 1 (x+1)- 1 x=1 (x-2)- 1 (x-3) is x=1

The solution of 1 x- 1 (x-1)=1 (x-3)- 1 (x-4) is x=2

The solution of 1 (x-1)- 1 (x-2)=1 (x-4)- 1 (x-5) is x=3

Rule: The solution of 1 [x-(n-2)]-1 [x-(n-1)]=1 [x-(n+1)]-1 [x-(n+2)] is x=n

x=-5.

The fractional equation is: 1 [x-(-5-2)]-1 [x-(-5-1)]=1 [x-(-5+1)]-1 [x-(-5+2)].

Simplify: 1 (x+7)- 1 (x+6)=1 (x+4)- 1 (x+3).

Solution: Set the cost of each refrigerator to be X yuan.

480 - x = x * 20% - according to the equation of the first three sentences: ** - cost = profit.

Solution: x = 400 -- the cost of each refrigerator is 400 yuan.

--In the above equation, the first three numbers calculate the income of 110 good refrigerators, the middle three numbers calculate the income of 10 broken refrigerators, and the last two numbers calculate the cost of 120 refrigerators.

Then, revenue - cost = profit (that is, 7680 yuan).

Answer: The take-home profit is 7680 yuan.

If you don't understand, you can ask

The cost of each unit (calculated according to good) 480 (1 + 20%) = 400 yuan, the profit of each unit (calculated according to good) 480-400 = 80 yuan, all good profits, 80x (120-10) = 8800 yuan, the unit price after 6% discount of damage.

The profit of 10 broken units is 10x (288-400) = -1120 yuan, and the final profit is 8800 + (-1120) = 7680 yuan.

Hello first calculate the cost of each unit: 480 (1 + 20%) = 400 yuan, then according to 480 yuan sold per unit profit = 480-400 = 80 yuan 480 60% = 288 yuan.

400-288 = 112 yuan, that is to say, ten of them were sold at a loss of 112 yuan each, so the actual profit = (120-10) 80-112 10 = 7680 yuan, please ask.

480 (1+20%)=400, the cost of refrigerators per day is 120*400=48000, the total cost of all refrigerators (120-10)*480+10*480*60%=52800+2880=55680, the total selling price of all refrigerators.

55680-48000=7680, actual profit.

480 yuan per unit, 20% profit, that is, cost 480 80% = 384 yuan, profit 480 20% = 96 yuan.

The profit of 110 refrigerators is 96 110 = 10560 yuan 10 broken refrigerators, 6% off**, 480 yuan per unit, 384-288 = 96 yuan per unit, a total loss of 960 yuan.

Therefore, the take-home profit of this batch of refrigerators: 10560-960 = 9600 yuan.

One: 480 (1 + 20%) = 400 yuan (purchase price) two: (120-10) * (480-400) = 8800 (** profit) three: 10 * 480 * 60% - 10 * 400 = -1120 (10 broken machine profits).

Four: 8800-1120 = 7680 (take-home profit).

Calculate the total cost first.

480*120 (1+20%)=48,000 yuan This is the money spent on these refrigerators, and then how much money is sold in total.

480 * 110 = 52,800 yuan This is the normal sale of 480 * 10 * yuan This is the 10 units discounted.

52800 + 2880 = 55680 This is how much money was sold in total, 55680-48000 = 7360 This is the profit.

480 (1+20%)=400 yuan, 480-400=80 yuan.

480 60% = 288 yuan.

400-288 = 112 yuan, actual profit = (120-10) 80-112 10 = 7680 yuan.

Step 1: Ask for a selling price.

According to the profit margin = (selling price - purchase price) purchase price.

Part 2: Profit = Total Selling Price - Total Purchase Price...

This question... It's so hard ... What grade are you? Little Six?