In the plane rectangular coordinate system, B and a are on the X and Y axes respectively, and the coordinate of B is (3,0) ∠ ABO = 30 degree AC bisection ∠ OAB intersects X axis at C (1) Find the coordinates of point C (2) If D is the middle point of AB, ∠ EDF = 60 °, (E on AC, f on BC), it is proved that CE + CF = OC

In the plane rectangular coordinate system, B and a are on the X and Y axes respectively, and the coordinate of B is (3,0) ∠ ABO = 30 degree AC bisection ∠ OAB intersects X axis at C (1) Find the coordinates of point C (2) If D is the middle point of AB, ∠ EDF = 60 °, (E on AC, f on BC), it is proved that CE + CF = OC

(1) OA = ob * Tan ∠ ABO = 3tan30 ° = √ 3; ab = √ (OA & # 178; + ob & # 178;) = 2 √ 3; ∵ AC bisection ∠ OAB, ∵ OC / CB = OA / AB = 1 / 2, that is, OC = ob / 3 = 1; the coordinates of point C are (1,0); (2) equilateral △ CDE & # 39;, refer to the figure: & nbsp; ∵ AC square ∠ OAB = 60 °, D is the midpoint of AB

In the plane rectangular coordinate system, the straight line y = - 1 / 2 x + B respectively intersects the x-axis at point a, and intersects the y-axis at two points of point B, and s triangle ABO = 4

A(-3/2,0) B(0,3)
Because P is on the line y = x, let p be (m, m)
Let AP intersect Y-axis at point h and make pf perpendicular to Y-axis at F
Because the area of △ ABP is bisected by the y-axis, s △ ABH = s △ PBH
That is AO * BH / 2 = BH * PF / 2
So Ao = PF
Ao = 3 / 2, so pf = 3 / 2
Since P is in the first quadrant, M = 3 / 2p is (3 / 2,3 / 2)

If the solution of the equation 9x-17-kx about X is an integer, find the value of K?

(9-k)x=17
x=17/(9-k)
k=8 ,-8

On the system of linear inequalities of one variable
A ballpoint pen is 2 yuan, a pencil is 1.5 yuan. If the number of ballpoint pens purchased is more than 2 times of the number of pencils, and the maximum number of ballpoint pens is 45, the total amount of ballpoint pens and pencils purchased is not less than 110 yuan, please help to calculate. There are several purchase schemes? How to purchase?

2x+1.5y>=110
x+y=

A set of data is known as: 20, 30, 40, 50, 50, 60, 70, 80, 50. The relationship between mean a, median B and mode C is ()
A. a＞b＞cB. c＞b＞aC. b＜c＜aD. a=b=c

The average is a = 20 + 30 + 40 + 50 + 50 + 60 + 70 + 80 + 509 = 50; in this group of data, 50 appears the most times, so C = 70; this group of data is arranged in the order from small to large (20, 30, 40, 50, 50, 50, 60, 70, 80), the number in the middle is 50, so B = 50

How many days are there from October 22, 2010 to November 30, 2012

2010.10.22-2012.10.22 is two years, 2012 leap year, a total of 365 + 366 = 731 days
From October 22, 2012 to November 30, 2012, the number can be counted as 40 days (both October 22, 2010 and November 30, 2012)
40 + 731 = 771 days

There are the following activities to buy books. If you buy 1-19 books, you can get 10% off each book; if you buy more than 20 books (including 20 Books), you can get 7% off each book, and each book costs 5 yuan
It's like two answers!
Class tickets are divided into two types: Class A and class B. class a bought five tickets and class B bought 35 tickets, which cost 125 yuan. Now everyone in the class goes to the cinema, so class B refunded five tickets. At this time, it actually cost 110 yuan. How much is the ticket price of class A and class B?

Are binary linear equations, according to the meaning of the two equations can be listed
If every time you buy a book is less than 20, there will be a result of 30 * 4.5 = 135, then there must be a time greater than 20 and a time less than 20
Let's set one X copy and one y copy,
X+Y=30；（1）
3.5X+4.5Y=110；（2）
(1) Formula equal sign about * 3.5 get 3.5x + 3.5y = 105 (3)
(2) Equation - (3) gives y = 5
We can get x = 25 and y = 5, that is 25 copies at a time and 5 copies at a time
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Suppose that the fare of a is X Yuan and that of B is y yuan
5X+35Y=125（1）
5X+30Y=110 （2）
(1) Equation (2) gives 5Y = 15
Substituting y = 3 into (2) yields x = 4
The ticket price of a is 4 yuan, and that of B is 3 yuan

Find the law 1.5,14.30. {}

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Who can help me solve the equation 5x (x + 6) + 2 = (x + 6) (10 + x)
I can't figure it out!

5x(x+6)+2=(x+6)(10+x)
5x^2+30x+2=x^2+16x+60
4x^2+14x-58=0
2x^2+7x-29=0
b^2-4ac=281
The remaining formula method with formula, don't think the number strange doubt the answer, the simplification is right
On the first floor, the answer is right
The second floor has been moved wrong

There are two bookshelves. If you take 12 books from the first bookshelf and put them on the second bookshelf, there are as many books on the two bookshelves. If you take 12 books from the second bookshelf, the number of books on the first bookshelf is three times that of the second bookshelf?

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