Some math problems have a high bounty score, and everyone must be 885

5,6*(x+1)=9*(x-1), x=5,36 people.

6，4x-60+3x=6x-63+7x 6x=-3 x=7,x+2x/3-1=4+3x/2-3 1x/6=2 x=128,4x/3-2=2-2x 10x/3=4 x=9,2(4x/3-2x/3+1/2)=5x/6 4x/3+1=5x/6 1=-x/2 x=-2

10,(4500*x-3000) 3000=5% x= so it's 7% off.

11,936/ h=

12. Set x hours to catch up with the front team. Then 4*(x+1)=12*xx=set to return in y hours. (12* hours.)

13. Let each payment be x yuan, then x+x=(8224-x)*x=4224

3 36

I don't have time, I'll send it later, I can't understand 3 questions, and I can't do 4 questions.

If a quadrilateral can be inlaid with a circle, then the diagonal sum of the quadrilateral is 180°, which is a theorem in junior high school.

Your question is incomplete and lacks conditions, you need to add conditions, complete the questions as follows.

A section of the highway runs parallel to the railway, and there are two people A and B traveling in the same direction on the highway. A walks, 5 kilometers per hour; B rides a bicycle and walks 15 kilometers per hour. A train came from behind, and the time it took for the train to chase A (from the time the front of the car just caught up with A to the time it just left A) was 36 seconds, and the time it took to catch B was 45 seconds.

Find the length of the train and the speed of the train.

Let the body length of the train be s kilometers and the speed of the train is v kilometers and seconds.

A's speed = 5 km/h, t1 = 36 seconds = 1 100 h;

B's speed = 15 km/h, t2 = 45 seconds = 1 80 hours.

v - 5)/100 = s

v - 15)/80 = s

v - 5 = 100s

v - 15 = 80s

20s = 10

s = kilometers = 500 meters.

v = 50 + 5 = 55 km h.

Let the train speed be x and the body length be y, from the question: 36 seconds = 36 3600 = 1 100 hours, 45 seconds = 45 3600 = 1 80 hours.

x-5)*1/100=y

x-15)*1/80=y

Solve the equation: x=55, y=

The length of the train body is km = 500 m, and the train speed is 55 km h.

, there's not a single unit of length, how did the above people make up the data?

The meaning of the title is not clear, can you explain more, the original title is certainly not like this.

A and B are stationary? Constant speed of the train?

1.(4a-9)+(3a-5)=0 gives a=2;

The square of a is -2a+1=4-2x2+1=1

2.Area s=axb+ squared 4 2 + squared 4 2 When a = 71, b = 30, s = 71x30+ squared 4 2 + squared 4 2

If B is the opposite of each other, then a+b=0, and if c and d are the reciprocal of each other, then cd=1;If the absolute value of x is 2, then x = 2;

x squared - ax + (-cd) to the 210th power - bx + (a + b) to the 2012 power - 3x = x squared - x (a + b) + (cd) to the 210 power + (a + b) to the 2012 power - 3x = 4 - 0-1 + 0 = 3