A math problem in the first year of junior high school, first aid, I can t think of it for a while

Equal. ao bisect angle cab then angle cao = angle bao and cd ab be ac then angle oea = angle oda and ad=ad

So the triangle aeo is all equal to the triangle ado

So oe=od

Angle OEA = Angle ODA i.e. Angle CEB = Angle ODB and Angle EOC = Angle DOB, so the triangle EOC is all equal to the triangle DOB

So OB is equal to OC.

Equal. Untie; cd ab at the point d, be ac at the point e cda= bea=90° perpendicular theorem

and ao bisector bac,be,cd intersect at the point o, do=oe The distance from the angle bisector to both sides of the angle is equal

and dob= eoc in the same plane with equal angles to the apex and cda= bea has been proven

do=oe has been verified

dob= EOC verified

dob≌△eoc〔asa〕

ob is equal to oc congruent triangles are equal to opposite sides

ao bisect bac

cao＝∠bao

Ao ao, cd ab at the point d, be ac at the point e oea oda 90 degrees.

oea≌△oda（aas），oe＝od

and coe bod (equal to the top angle).

OEC ODB 90 degrees, OE OD

coe≌△bod（aas）

oc＝ob

1.When the number of people traveling to the hidden tank is 25, travel agency A pays a fee of 25*660*yuan; B travel agency pays 23*660* yuan.

When the number of tourists is 40, travel agency A pays 19,800 yuan; B travel agency paid 20,064 yuan.

2. Let the number of people be x

660*x* solves the equation x=32

3. When the number of people is less than 32, it is more suitable to choose travel agency B; When the number of people is greater than 32, it is more cost-effective to choose travel agency A; When the number of people is equal to 32, the two travel agencies are equally cost-effective.

There are x people in class A and y people in class B.

According to the title, 300 < 6+9(x-1) <400

300 < 13+8(y-1) <4006+9(x-1)=13+8(y-1)

Solve 33 2 3 < x < 44 7 9< y <

9x-3=8y+5

x=8y+8/9

Because the number of people must be an integer.

So 34 is less than or equal to x less than or equal to 44

37 is less than or equal to x less than or equal to 49

and x is a multiple of 8.

8y+8 is a multiple of 9.

So x=40, y=44

x+y=40+44=84

The number of students in Class A and Class B is 84.

Set the number of donors in class A as x, the number of donors in class B as y, and the donation in class A as 6 + (x-1) * 9 that is, 9x-3

The donation for Class B is 13+(y-1)*8, i.e. 8y+5

Then 9x-3=8y+5, i.e. (x-8) (y-x)=8 and 300<9x-3<400

So x is 34 to 44, and x-8 is an integer from 26 to 36, and y-x is an integer, so can be a multiple of 8, only x-8=32, that is, x=40, so y-x=5, so y=45

So the sum of the numbers is 85

- (4 ) 3 ) 2 = 5 +(4 ) 3 ) 2 )

Did you make a mistake in this question? According to the title, it seems to be the formula I wrote above.

If you are not mistaken, then:

Since 5 - 4 ) 3 ) 2 = 4 then another 5 + (2 ) = 3 + = 4

So ( )1

So you can fill in 1, 0 or 0, 1 or 2, -1 and so on.

2.Because ab Opposite numbers.

So a+b=0

Because the absolute value of m is 3

So m = 3 or -3

So when m=3, the original formula = 0 5+3*3+1=10 and when m = -3, the original formula = 0 5+(-3)*3+1-8

-4 ) 3 ) 2 = 5 +(4 ) 3 ) 2 )

2. A and b are opposite to each other, so a+b=0

The absolute value of m is 3, so m = 3 or -3

a+b) 5+m+1=m+1=4 or -2

So the answer is 4 or -2

1 -3 ，4

2 a .b is the opposite of each other, so a+b=0;

m|=3, then m=3 or m=-3;

The answer is: 10 or -8.

Question 1: 5 - 4 ) 3 ) 2 = 5 + (4 ) 3 ) 2 ).

Question 2: Because of Ab is the opposite of each other, so.

sa+b=0, so.

a+b）/5+3m+1=3m+1

The absolute value of m is 3

So m = 3 or -3

then 3m+1=10 or -8

If two people cooperate for x days, then 1 and eliminate 6 + (1 4 + 1 6) x=1, x=2, then A's workload is disturbing Wang 1 4 * 2 = 1 2, and B's workload is 1 6 + 1 6 * 2 = 1 2, and the ratio of the workload of the two is 1: slow boy 1, so 600 yuan is paid to each person 1 2 is 300 yuan.

Vegetable rice area = (top bottom + bottom bottom) * height 2

a+b)*(b-a)/2

When a=10 b=30

Vegetable rice area = (a+b)*(b-a) 2

Dear, we have learned that two identical trapezoids can be put together into a parallelogram, so the area of the vegetable field is 2b (b-a).

Make an auxiliary line first, extend the connection of two (b-a) lines, then the area of the vegetable field is b square - a square. When a=10 b=30, the area of a trapezoid is (a+b)x(b-a)=(10+30)x(30-10).

<> then substitute a=10 and b=30 into the above formula.

Well, the trapezoidal area is divided by 2 and the total area of the vegetable field is multiplied by 2 and finally 80

This question is not difficult, maybe you usually have less contact with the bits and pieces of life, to know more about life, it will be helpful for everything! The answer to this question is as follows:

1. Positive direction.

2. Explain that the shelf life is 20 days or months, and the top is closed and slippery, and the bottom is horizontal, indicating that the temperature of the food is stored in the range of minus 3 degrees to minus 3 degrees.

3. +19 (note that the first floor of the surface sedan is the 0th layer), -5,124, indicating that the change of the commodity ** (whether it is a price increase or a price reduction) is 10% of the original price.

Hope it helps!

Professional Answers).

The woodcutter used to have x money, so he had 2x money when he came back the first time, and 2x money before the second departure (2x-24);

So when you come back the second time, you have money 2 (2x-24), and before you leave the second time, you have money 2 (2x-24)-24;

So the third time I came back, I had money 2, and I had it left after paying the money.

2-24, at this time the woodcutter has no money.

The equation can be listed as: 2-24=0

So x=21

Answer: Slightly.