[urgent!] (x + 2Y + 3Z) &=________________ 205²= 299²=

x²+4y²+9z²+4xy+6xz+12yz
(200+5)²=40000+25+2000=42025
(300-1)²=90000+1-600=89401

（x+2y-3z）² 1999² 2005²-20042006 （4-3a）（-3a-4）（a-1）（a+1）（a²+1）
retransmission
（1）（x+2y-3z）²
（2） 1999²
（3）2005²-20042006
（4）（4-3a）（-3a-4）
（5）（a-1）（a+1）（a²+1）

（1）（x+2y-3z）²=x^2+4y^2+9z^2+4xy-12yz-6xz（2） 1999²=(2000-1)^2=2000^2+1-4000=4000000+1-4000=3996001（3）2005²-2004*2006=2005^2-(2005^2-1)=1（4）（4-3a）（-3a-4）=(-3a)^2-4^2=9a^2-16...

Set the fixed point m (- 3,4), the moving point n moves on the circle x + y = 4, make the parallelogram MONP with OM and on as both sides, and find the trajectory of point P

Let P (x, y), n (x0, Y0), and x0 + Y0 = 4 be equal according to the corresponding sides of the parallelogram, so the distance from P to m is equal to the distance from n to o, | PM | = | no |, (x + 3) + (y-4) = (x0-0) + (y0-0), so (x + 3) + (y-4) = 4

Given the function f (x) = 2 ^ X-2 ^ - x, and the sequence {an} satisfies f (log2an) = - 2n, find the general formula of an

f(x)=2^x-2^(-x)
f(logan) = -2n
an - 1/an =-2n
(an)^2 + 2n(an) - 1=0
an = -n+√(n^2+1)

The standard of taxi charge is: 5 yuan within 3 kilometers (including 3 kilometers), 1.20 yuan per kilometer for the part over 3 kilometers (less than 1 thousand yuan)
The charging standard of taxis in this city is: 5 yuan for less than 3 kilometers (including 3 kilometers), 1.20 yuan for each kilometer for more than 3 kilometers (less than 1 kilometer is calculated as 1 kilometer), and 0.60 yuan for air return. (1) set the driving distance as X kilometers (x is greater than or equal to 3 and takes an integer), and use X to express the algebraic formula of Y yuan. (2) when the charging is 10.40 yuan, The driving distance of the car is not more than several thousand meters. What is the range of the distance?

y=（5 (x

Nail a rectangle with a piece of wood and pull it into a parallelogram along the diagonal. Compared with the original, the area {} A is unchanged, B is larger, C is smaller

Because the rectangle is drawn into a parallelogram, the bottom does not change, but the height becomes smaller
So the area becomes smaller
Choose C

Let f (x) = AX-1, G (x) = a5x + 3, where a & gt; 0
If f (x) is less than or equal to G (x), find the value range of X

f(x)=a^(x-1),g(x)=a^(5x+3)；
f(x)≤g(x) → a^(x-1)≤a^(5x+3)；
If a

On April 14, 2010, Yushu County, Qingkai Province, was hit by a 7.1 magnitude earthquake, which affected the hearts of the Chinese government. After the Youth League branch of a school proposed to donate money to the disaster area, all the teachers and students of the school donated 450 million yuan. Among them, the students donated 9000 yuan less than twice as much as the teachers
Column with answer

Analysis: there are two equal relations in this question: Teacher's donation + student's donation = 45000, student's donation = 2 × teacher's donation - 9000. Set two unknowns, and list binary linear equations according to the above equal relations
If teachers donate X Yuan and Students Donate y yuan, there will be
y=2x-9000
x+y=45000
The solution is: x = 18000, y = 27000
A: teachers donate 18 000 yuan and students 27 000 yuan

P is the point out of the plane of the parallelogram ABCD, m and N are the midpoint of AB and PC respectively, and the plane padn is the plane PBC = L
(1) : Verification: BC ‖ L
(2) Is mm parallel to planar pad

(1) Make a straight line PP1 / / BC on the pad, then PP1 / / AD, then PP1 is also on the plane PBC, that is, PP1 is l, so BC / / L
(2) Parallel. If the midpoint of CD is e, then me / / AD, and in triangle PCD, NE / / PD, then MNE / / APD, then Mn / / pad

It is known that a * 4 out of 3 = 11 out of 12 * b = 5 out of 5 * C, and a / B / C is not equal to 0. Arrange a / B / C from large to small to explain the reason

4/3＞5/5＞11/12
Therefore, b > C > a
Reason: the product is equal, the greater one factor, the smaller the other factor

[urgent!] (x + 2Y + 3Z) &=________________ 205²= 299²=