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1. Solution: the second side: (a+3b)+2a=3a+3bThe third side: 2 3(3a+3b)+2a=2a+2b+2a=4a+2bCircumference = 8(a+3b)+(3a+3b)+(4a+2b)=88(a+b)=8

a+b=1 The second edge is 3a+3b=3(a+b)=32, solution: x=-3, y=7

243*a-27b-3c-5=7

243a+27b+2\3c=-12

When x=3, y=243a+27b+3c-5=-12-5=-17

The first side is a+3b

The second side length a+3b+2a=3a+3b

The third side length 2 3 (3a+3b) + 2a = 4a + 2b triangle circumference is a + 3b + 3a + 3b + 4a + 2b = 8a + 8b = 88 (a + b) = 8

a+b=1 The length of the second side is a+3b+2a=3a+3b=3(a+b)=3y=ax5+bx3+cx-5, when x= 3, y=77=ax5+bx3+cx-5

So, when x = 3, ax5+bx3+cx=7+5 and when x=3, ax5+bx3+cx=-(7+5)=-12ax5+bx3+cx=-12

ax5+bx3+cx-5=-12-5=-17

1.First side: A+3b

The second side: a+3b+2a=3a+3b=3(a+b) the third side: (3a+3b)*2 3+2a=4a+2b, so the perimeter = a+3b+3(a+b)+4a+2b=8(a+b)=8, so a+b=1, then the second side is 3(a+b)=32

Look directly at the item about x.

Because x is to the odd power, when x takes the opposite number, the value of y is also the opposite number, so y=-7

Hello: Triangle Perimeter:

a+3b)+(a+3b+2a)+(a+3b+2a)* 2 3+2aa+2b+a+2b+2a+(3a+3b)*2 3+2aa+2b+2b+2a+2a+2a(1+1+2+2+2)a+(2+2+2)b8a+6bIf the circumference is 8cm, the second side is:

The first edge: a+3b

The second edge :(a+3b)+2a=3a+3bThe third edge :(3a+3b)*3 2+2a=4a+2bThe perimeter is: a+3b+ 3a+3b+ 4a+2b=8a+8b=8, you can get a+b=1

The second edge is 3a+3b=3(a+b)=3

Suppose x cm lead is used, then the volume of 10 lead balls is:

s=10*(4/3)*pi*(12/2)^3;

Since the volumes should be equal, so.

s=x*pi*(12/2)^2;

The above two formulas are equal:

x*pi*(12 2) 2=10*(4 3)*pi(12 2) 3 can find that x is equal to 80 centimeters.

Solution: Scheme 3x15=45 tons 48-45=3 tons 2200x45+500x3=100500 yuan Scheme design, x days of special orange juice, then it takes 15-x to make ordinary orange juice, and 4x+3 (15-x)=48 according to the title

x = 33x4x2500 + 3x12x2200 = 109,200 yuan A: If the company adopts the plan, it can make a profit of 100,500 yuan;

If the company adopts the plan, it can make a profit of 109,200 yuan.

Solution tons x 15 = 45 tons 48-45 = 3 tons. 45 tonnes of special orange juice are produced in 15 days, and 3 tonnes of fresh sweet oranges are sold directly.

2. Set, x days to make special orange juice, then it takes 15-x to make ordinary orange juice; According to the title, 4x+3(15-x)=48, x=3 days.

Answer: If the company adopts the plan, it can make a profit of 2200x45 + 500x3 = 100500 yuan;

If the company adopts the scheme, it can make a profit of 3x4x2500 + 3x12x2200 = 109200 yuan. FYI!

Problem 1, solution 15 * 3 * 2500 + (48-15 * 3) * 500 = 114000 (yuan).

Question 2, solution, let's use x days to make special orange juice.

3x+(15-x)*4=48

x = 12 (days).

I'll answer.

The vendor gave the farmer a total of buckets and rice.

The weight of the iron drum is not more than 19 catties, assuming that the weight of the iron drum is 1

Corn 45 iron drum 1 rice 18

Iron bucket 1 rice.

Let's say the weight of the iron bucket is 2

Corn 44 iron drum 2 rice.

Iron bucket 2 rice.

Finally, it is assumed that the weight of the iron drum is 18

Corn 28 iron buckets 18 rice.

Iron bucket 18 rice.

Therefore, the peasant woman was not profitable in this transaction, and the greater the weight of the bucket, the greater her loss.

If you don't understand, you can contact me, I'm helping you answer.

Set the barrel weight x.

then the corn weighs 46 - x

It should be replaced with rice (46 - x).

Rice - x

Difference = (46 - x) - x) = - 2x 5 - x = 3x 5 > 0

Therefore, it is not cost-effective to exchange less rice than should be exchanged.

Not cost-effective!

Assuming that the weight of the barrel is 6 catties, the weight of the corn is 40 catties.

The fair case should be: 40 catties of rice.

But in fact, it was a catty, and the peasant woman only got a catty of rice, which was less than the fair situation.

If it is not cost-effective, assuming that the barrel weighs 1 catty, the original corn is 46-1=45 catties, which should be able to exchange for 45 catties of rice, but she actually only changed catties.

If the number of gymnastics teams is 5x, the number of basketball teams is 6x, and the number of volleyball teams is 10x-5

6x + 3*(5x) = 42

21x = 42

x = 2 gymnastics team size = 5 * 2 = 10 (people) basketball team number = 6 * 2 = 12 (people).

Number of volleyball team = 10*2-5=15 (people).

If the gymnastics team is x, the basketball team will be 6 5x, and the volleyball team will be 2x+5

6/5x+3x=42

x=10

There are 5t people in gymnastics, 6t in basketball, and 2x5t-5 in volleyball.

The columnable equation is 6t+5tx3=42

There are 10 gymnastics, 12 basketball, and 15 volleyball.

Solution (1) Arbitrarily write a three-digit number 763

The second three-digit number is 367 (the first three-digit digit is swapped with the hundred), the third three-digit number is 396 (the difference between the first and second digits, the difference between the large number and the decrement), and the fourth three-digit number is 693 (the third three-digit digit is swapped with the number in the hundred).

3. The fourth three-digit sum is summed.

Conclusion: Write a three-digit number arbitrarily, and after the above transformation, the first.

3. The sum of the fourth three-digit number is 1089

2) Write an arbitrary three-digit number, abc(a>c).

The value of this three-digit number is 100a+10b+c

The value of the second three-digit number is 100c+10b+a (the first three-digit digit is swapped with the hundred).

The value of the third three-digit number is.

100a+10b+c-（100c+10b+a）=100（a-c）+(c-a)

100 (a-c-1) + 90 + (10 + c-a) (the difference between the first three digits and the second three digits).

The value of the fourth three-digit number is 100 (10 + c-a) + 90 + (a-c-1) (the single digit of the third three-digit digit is swapped with the digit on the hundred).

Clause. 3. The fourth three-digit sum is summed.

100(a-c-1)+90+(10+c-a)+ 100(10+c-a)+90+(a-c-1)]

100a-100c-100+90+10+c-a+1000+100c-100a+90+a-c-1

(2) abc(a c) cba a-1-c)(b-1+10-b)(c+10-a)] square brackets are the third number, three small brackets respectively represent hundreds, tens, and units, c-a on the single digit is not enough to subtract, to the ten digits to borrow one, so it is c+10-a, ten b-b, but has borrowed one, it is not enough to subtract, only to the hundred to borrow one, so it is b-1+10-b=9, the hundred also borrowed one, of course, it is a-1-c; Swap the single digits and hundreds to get the fourth number: [(c+10-a)(b-1+10-b)(a-1-c)], and add the third and fourth numbers: [(a-1-c)(b-1+10-b)(c+10-a)]+c+10-a)(b-1+10-b)(a-1-c)]=9)(18)(9)]=1089

Ten is equal to 18, it should be advanced to the hundred, the remaining 8 is ten, the ten is originally 9, and the ten is 10 after getting the ten digits, and it should continue to advance to the thousand, and the remainder 0 will become the hundred.

Therefore, abc takes a three-digit number composed of any number (a c), and the result calculated according to the title is 1089!

To ABC, the second digit CBA.

The third number.

abc - cba = 100a + 10b + c - 100c + 10b + a) =99a - 99c = 99(a - c) =100（a - c） -a - c) 。

Obviously a-c is a single digit. Let a - c = k, then the third number is equal to 100k - k, which must be such a number in form:

Hundred digits = k - 1, ten digits = 9 , single digits = 10 - k

Thus the fourth number form is 10 - k in hundreds, 9 in ten, and k - 1 in units

then the sum of the third and fourth numbers.

100(k - 1) +90 + 10 - k) +100(10 - k) +90 + k - 1)

100k - 100 + 180 + 10 - k + 1000 - 100k + k - 1

1. Specific digital control.

321-123 = 198 --- third number.

891 --- fourth number.

546-645=99 – the third number.

990 – the fourth number.

Conclusion: Whatever the three-digit number is, the sum of the third and fourth numbers is 1089

2. Proof: The first number is ABC, and the second number is CBA

abc-cba

100a+10b+c-(100c+10b-a)=100(a-c)-(a-c)

Now we need to convert the above equation to 100*()10*() and set a-c= f

Then the above equation = 100f-f

100*f+90-90-f

100f+10*9+10-100-f

100*(f-1)+10*9+(10-f)--finally into the form we want, this is the third number, the single digit is 10-f, the tenth digit is 9, and the hundred digit is f-1

So, the fourth digit is in the first place.

Then the fourth digit is f-1, the tenth digit is 9, and the hundredth digit is 10-f, and the third number + fourth digit is f.

100*(f-1)+10*9+(10-f)+100*（10-f）+10*9+（f-1）

100（f-1+10-f）+180+（10-f+f-1）

The first number is a b c

The second number c b a

The third number a-1-c 10+b-1-b 10+c-a, the fourth number: 10+c-a 10+b-1-b, a-1-c, sum 10, 8, 9

The conclusion is that the sum of the third number and the fourth number does not change, 1089. But it seems that there is another condition, (abc is not equal to 0).

1.Assuming that drink A needs to be configured with x kg, please write the group of inequalities that meet the problem and find the solution set.

Solution set 28 x 302

If the cost per kilogram of beverage A is 4 yuan, the cost of beverage B is 3 yuan per kilogram.

Try 1As a result, the total cost of the two beverages of A and B is explored when the number of kilograms of beverage A and B is the smallest w: a:x 28w28x4 (50 28)3 178 yuan b:

x 29 W 29x4 (50 29) 3 179 Yuan C: x 30 W 30 X4 (50 30) 3 180 Yuan When x 28, the total cost of the two beverages A and B W is the smallest.