A newspaper math problem that seems to have been done but can't be done The purchase price of the evening paper is 0.7 yuan per copy and the price is 1 yuan per copy. The newspapers that cannot be bought are returned at 0.2 yuan per copy. In a month (30 days), 100 copies can be sold every day for 20 days, and only 60 copies can be sold every day for the remaining 10 days. However, the number of copies per day must be the same. If x copies of the evening paper are bought every day, the monthly profit is y yuan (1) The functional relation between Y and X and its domain of definition (2) How many newspapers should I get in every day? What's the biggest profit every month?

I can't use the equation to solve the problem, but I can only analyze it. According to the meaning of the problem, we can set up the equation x * 20 * (1-0.7) - (X-60) * 10 * (0.7-0.2) + 60 * 10 * (1-0.7) = y, and get the solution: x + 480 = y once a yuan

Answers to sixth grade mathematics newspaper answers to sixth grade mathematics newspaper

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Find the rule 48,24,72,36108, ()

54, analyzable: (6x8, 6x4) (, 6x12, 6x6), 6x18, so it should be 6x9 = 54

Use the nine numbers 1, 2, 3, 4, 5, 6, 7, 8 and 9 to form prime numbers. If each number has to be used and can only be used once, how many prime numbers can these nine numbers form at most?

Can be composed of the following prime numbers: 2, 5, 7, 61, 43, 89, a total of 6. A: then these 9 numbers can be composed of up to 6 prime numbers

Let f (x) be a function defined on real number r. if f (0) = 1 and for any real number AB, f (a) - f (a-b) = B (2a-b + 1), then f (x) is analytic

Let a = b = x, then f (a) - f (a-b) = B (2a-b + 1) can be reduced to
f（x)-1=x(x+1)
f(x)=x^2+x+1

What's the next two number?40,24,26,12
What's the next two number

The next two are 10 and 9

Decompose the square of factor x-9y-4z + 12yz

x²-9y²-4z²+12yz
= x²-（9y²+4z²-12yz）
= x²-（3y-2z）²
=（x+3y-2z）（x²-3y+2z）

Elementary three column quadratic equation of one variable to solve practical problems
1. A large number of New Year cards were bought at the gift counter of a shopping mall during the Spring Festival. One kind of New Year cards can sell 500 pieces a day on average, with a profit of 0.3 yuan per card. In order to reduce inventory as soon as possible, the shopping mall decided to take appropriate price reduction measures. The survey found that if the price of this kind of New Year cards is reduced by 0.1 yuan, the shopping mall can sell 100 more cards per day on average, and the shopping mall wants to make an average profit of 120 yuan per day, How much should be reduced for each card?
2. For a certain kind of clothing, 20 pieces can be sold every day on average, and the profit is 44 yuan per piece. If the price of each piece is reduced by 1 yuan, 5 pieces can be sold every day. If the profit is 1600 yuan per day, how much should the price be reduced?
3. There are 100 peach trees in an orchard. One peach tree has 1000 peaches on average. First, we plan to plant more peaches to increase the yield. The experiment shows that for every additional peach tree, the yield of each peach tree will decrease by 2. If the yield increases by 15.2%, how many more peaches should be planted
Urgent, strive for no answer before tonight, it doesn't matter, as long as there is an accurate formula, of course, the answer is better

1. The price of each card should be reduced by X Yuan
(0.3-x)(500+x/0.1*100)=120 x=0.1
The price of each card should be reduced by 0.1 yuan
2. The price of each piece should be reduced by X Yuan
(44-x)(20+x/1*5)=1600
x=4
3. X peach trees should be planted
1000*100*(1+15.2%)=(100+x)(1000-2x)

The volume of a swimming pool is 1200 ()
I read the answer, it's 1200m3, but it's too big. What is it?

This is normal. A standard swimming pool is 50 meters long, 25 meters wide and 1.8 meters deep. Its volume is 50 * 25 * 1.8 = 2250m3. So 1200m3 is not big

How to write the simple operation of 61 + 4 times 610 + 59 times 61

61+4×610+59×61
＝61×1＋40×61＋59×61
＝61×（1＋40＋59）
＝61×100
＝6100