Math problems in the first year of junior high school today 08 30 before the fast bonus points

1) A: y=5*30+(x-5)*5=5x+125B: y=

2) When the two y's are equal, the cost is the same, that is, 5x+125=, so x=20. That is, the cost is the same for 20 boxes.

3) When 15 boxes, the cost of home A is 15 * 5 + 125 = 200 yuan, and the cost of family B is , at this time go to home A.

When there are 30 boxes, the cost of home A is 30 * 5 + 125 = 275 yuan, and the cost of family B is, at this time, go to home B.

1.Store A: 30*5+5*(x-5).

Shop B: 30*5*

2.From (1), 30*5+5*(x-5)=30*5*, the solution, x=20 boxes A: 30*5+5*(15-5)=200 B: 30*5*

So, when you buy 15 boxes, go to store A and buy them.

When 30 boxes, A: 30*5+5*(30-5)=275B: 30*5*

So, when you buy 30 boxes, go to store B and buy them.

If Y dollars should be paid, then.

1) Y A = 150 + 5 (x-5) = 5x + 125 Y B = 135+

2)5x+125=135+

x=203) when x=15, get:

yA=200 yuan, yB=yuan.

So go to A's house and buy it.

When x=30, get:

yA=275 yB=270.

So go to B's house and buy it.

1) A: 5 30 + (X-5) 5 B:

2) 30 5 + (x-5) 5 = 30 5 + solution x = 503) A: 15 30 + (30-15) 5 = 525 B: 15 30

I chose to go to the nail.

1. Store A needs to pay: 125+5x

Shop B pays: 135+

2. 20 boxes.

3. When you buy 15 boxes, it costs less to go to store A, and when you buy 30 boxes, store B costs less.

1...A 150+5 (X-5) B.

2...125+5x=135+ x=20

3...15 is less than 20 to go to A 30 is greater than 20 to go to B.

3m + 2n power = 3m power of 10 + 2n power of 10 = 64 + 25 = 89 to the power of 2m + 3=(x-1) 2+3=x 2-2x+4 to the power of 4 times the power of 8 = 2 7 times 2 6=2 13 n=134 You can compare the size of 2 to the 4th power and the 3rd power of 3, (they are all 100 or 75 divided by 25), you can compare the size of 2 to the 100th power and 3 to the 75th power (the truth is high school).

1 Let the original form =s

2s=1+2 2+3 (2 squared)+. 10 2 to the 9th power.

s=2s-s=1+1 2+1 (2 squared)+.1 2 to the 9th power - 10 2 to the 10th power.

The front is a series of proportional numbers, and with the formula you can find =2 (1-1 2 to the tenth power) and subtract the last term, and finally =2-3 2 to the 8th power = 2-3 64 = 125 64

2 Set 1 2+1 3+·· 1 2010=a1 2+1 3+·· 1 2009=b

Original formula = ax(1+b)-(1+a)xb=a+ab-(b+ab)=a-ba-b=1 2010 (the first 2009 terms are the same).

It should all be equal to 0 - I'm a sophomore.

3. (x square y squared) [(x square y squared)-1] = 12 (x square y square) square - (x square y square) - 12 = 0 to get (x square y square) + 3 = 0 or (x square y square) - 4 = 0 so (x square y square) = -3 or 4

4、(2x-3y)(2x+y)=5

5', solution: a (a a 1) 1 6

a²＋a＋1）/a＝6

a＋1/a＝5

a＋1/a）²＝5²

a²＋1/a²＝23

a^4＋a²＋1）/a²＝a²＋1/a²＋1＝23＋1＝24∴a²/（a^4＋a²＋1）＝1/24

xy is the inverse number of the phase bond of the reed hole, x+y=0, m, n are the reciprocal of each other, mn=1, the absolute value of a is 2, m(x+y)+|a|-mn=0+2-1=1

(1) The number of squares and the number of absolute values are not less than 0.

And the sum of these two is 0

Then there must be two numbers that are both 0

i.e.: m-6 0 and n-m+4 0

m=6,n=2

2) ab=6, ap=2pb, so p is the 3rd aliquot ap 4, pb 2

Point Q is the midpoint of Pb, so Qb 1, AQ 6-1 5

From the nonnegativity of the absolute value of the square to get m 6 0, n m 4 0, the solution is m 6, n 2.

When p is on the left side of a, there is no solution; When P is between AB, AP 4, PB 2, PQ 1, AQ 5;When P is on the right side of B, AP 12, PB 6, QB 3, AQ 9.

(1):m=6,n=2

I don't know the second question very well, I hope the first question will be helpful to you.

Take the largest set of numbers so that it is representative, and if the number is too small, it will be accidental and not enough to illustrate the facts.

9008 10000 is about 90 percent

The results are expressed as decimals and are accurate.

The answer is definitely.

1.（1+3+5+……99+101）

2-100=-102；3+99=102，-4-98=-102；cancel each other out, and in the end 51 remains

Add brackets for every two items and calculate. The result should be 51

1-2=-1

So bai1-2+3-4+5***100=fifty (duzhi100 2=50).

DAO minus one is added up, i.e. (100 2) * (1) = -50 so 1-2 + 3-4 + 5 *** 100 + 101 = (100 2) * (1) + 101 = 51

Equal to the solution: original formula = 102-102 + 102-102 ......102-102 + 51 = 51 (that is, the sum of the beginning and the end of a total of 25 groups of 102-102 is equal to 0, and there is a special genus 51 in the middle).

2 solution: original formula = -1-1-1......-1 + 101 = -50 + 101 = 51 (there are 50 -1).

Add a parenthesis for every two copies. It's like bai

This makes a total of 50 parentheses.

If the number in each parenthesis is -1, then the 50 parentheses add up to -50 and add 101 at the end

Get 51

1 Left Right.

2 x is greater than or equal to 0 (the symbol is written by yourself, and cannot be typed).

The loss was 500,000 yuan.

2.Walked 150 meters to the east.

3.80 tons of rice were delivered. Wish.