Heroes, help! Poor in math and can t write!! Extra points after writing!!

>5x+3

2x<-8

x<-4

x=m-3,y=5-m

x>y, i.e. m-3>5-m, m>4

15. Xiaoying's household water is more than 5cm3

Set up water with xcm 3

Then there is (x-5)*2+9 15

x≥87.There are x rooms.

8(x-2)<5x+5<8(x-1)

13 3 And because x is an integer, x=5or6

When x=5, there are 5*5+5=30 people.

When x=6, there are 6*5+5=35 people, which contradicts the question and is discarded.

In summary, there are 5 dormitories with 30 female students.

1)x/2-5>=3

2)x<-4

4)60<=x<=80

5) Multiply the left and right sides of the equation to obtain: 6x 2+7xy+2y 2=m 2-1, and when m=1, x>y

6) Set water x: >=15

9+2x-10>=15

x>=8

Let A be x and B be y

to get a system of equations. 3/8x=2/5y

1/4x-1/5y=4

Solve the equation. y=60 x=64 I don't know if you can understand it.

13、(1)

How many times is it a monomial?

Let's say it's 4 times.

then 2+(a-1)=4

a=3a²+2a+1

a+1) If not 4 times, the method is the same.

And the values of a +2a+1 and (a + 1) are equal.

14. The number of times is the same.

then m+(n+2)=(m+2)+(4-n).

m+n+2=m+2+4-n

2n=4n=2

As shown in the figure, the same two wheels A, B radius R1 = 10CM, connected with a conveyor belt, C wheel radius R2 = 5CM, connected with the motor shaft. It is known that the speed of the motor is n=300rad min, and there is no slippage between the C wheel and the A wheel, and between the AB wheel and the belt. The object p slides onto the conveyor belt from the left end with the horizontal initial velocity of v0=1 m s, and the dynamic friction factor between p and the conveyor belt u=,a,b is 2m, find:

1, What is the angular velocity of the B wheel? 2, object p with.

If there are 20 stations, and each of the two adjacent stations is about 1 km apart, then there are 19 stations with a total of 19 km, which is the definition domain x n (natural number), and 0 x 19f(x) = 2, 0 x 5

3，5＜x≤10

4，10＜x≤15

5，15＜x≤19

The function is a jump function (truncated), and the image has a solid point and a hollow point (note this).

Solution: 1) A product produces x pieces, then chain mountain B product produces 50-x pieces of clever calling wheels.

So it is needed: A: 9x+4(50-x)<=360 B: 3x+10(50-x)<=290

9x+4(50-x)<=360

9x + 200-4x "filial piety = 360

5x<=160

x<=32

3x+10(50-x)<=290

3x+500-10x<=290

7x>=210

x>=30

30<=x<=32

So x=30,31,32

50-x=20,19,18

So there are 3 kinds.

A30 pieces, B20 pieces.

A31 pieces, B19 pieces.

A32 pieces, B18 pieces.

9x+4(50-x)≤360

3x+10(50-x)≤290

Solution (1).

30≤x≤32

When x=30, 50-x=20, the remaining A raw material is 360-9x-4(50-x)=10, and the remaining B cosporium is 290-3x-10(50-x)=0

When x=31, 50-x=19 is 360-9x-4(50-x)=5, and 290-3x-10(50-x)=7

When x=32, 50-x=18, the remaining A raw material is 360-9x-4(50-x)=0, and the remaining B raw material is 290-3x-10(50-x)=14

1) a--x then b is (guess 50 x).

9x＋4(50－x)≤360

3x＋10(50－x)≤290

2) Solve the inequality group: 30 x 32 (x is an integer), so x can be used to justify the three kinds of Lingzhao ruler deficiency cases.

y'=3x^2

So the slope of the tangent at point p is: 3*1 2=3

So the tangent is: y-12=3(x-1).

y=3x+9

The intersection points with the y-axis are: x=0, y=9

So the ordinate of the intersection is 9

The derivative is obtained first, and then substituted for the x-point coordinates, and the tangent slope is known as the slope k, and the linear equation for the crossing point (a, b) is:

y-b=k(x-a)。。

Knowing p(1,12), let y-12=k(x-1) so x 2+11=k(x-1)+12 , x 2-kx+k-1=0 can be seen from the problem, there is only one intersection point. So =0 , k 2-4(k-1) = 0 solution k=2, so y=2x+10 , so the ordinate is (0, 10).

In the college entrance examination, if this question is 12 points, it should have 2 points.

1)y=√(5+4x-x^2)

i.e. 5+4x-x 2=(5+x)(1-x)>=0, i.e., 5+x>=0 1-x>=0 or 5+x<=0 1-x<=0=> 1=>x>=-5 or x<=-5 and x>=1 The latter set has no solution.

So the definition domain is 1=>x>=-5

2)f（x-1/x）=x2+1/x2+1

Let x-1 x=a

Then there is (x-1 x) 2=x 2+1 x 2 -2=a 2 ==x 2+1 x 2=a 2+2

So there is f(a)=a 2+3

So f( 2-1)=(2-1) 2+3=6-2 23)f(x+1) is , then there is -2<=x<=3==>1<=x+1<=4

So there is -1<=2x-1<=4 ==0<=x<=5 2 So the definition domain of the function y=f(2x-1) is 0<=x<=5 2 I can help you, you set me first, and I will teach you.

I don't understand, please tell me if you have an answer.

There are two cases in this problem, first, ab is on the same side as cd, doing of of perpendicular to cd and intersecting with ab with the point e, with ob and od

Because the diameter of 50 and because of the chord ab cd, from the chord cut theorem, ae is equal to be, df is equal to cf, and the square of 25 minus the square of 24 is equal to 49

The root number 49 is equal to 7, so oe is 7 25 squared minus 20 squared to get 225 225 square root is 15

So the distance between AB and CD is 8 with an OF of 15

When AB and CD are opposite, the distance between AB and CD is 7 plus 15 equals 22

For chord AB, d1 = root number ((50 2) -40 2) ) = root number (225) = 15;

For chord cd, d2 = root number ((50 2) -48 2) ) = root number (49) = 7;

Considering the position of AB and CD, there are:

When they are on the same side of the parallel diameter, d=d1-d2=8cm, and when they are on different sides of the parallel diameter, d=d1+d2=22cm.

The distance from circle o to chord ab is h1 = 25 20 = 15 the distance from circle o to chord is h2 = 25 24 = 7 When ab and cd are on the same side of the center of the circle o, the distance between the two strings is h1 h2 = 8 When ab and cd are not on the same side of the center of the circle o, the distance between the two strings is h1 h2 = 22

The distance between AB and CD is 56I remember that I had heard this question from the teacher before. Additional questions on the test paper, forgetting ...... in the process