English translation Halloween, pumpkin head, step on... Up, all of a sudden Put... On (e.g. put pumpkin head on Jake's head), trap, climb up from These are the words, What we want is the level of junior high school students, don't make those difficult words I'll use it tomorrow afternoon at the latest

halloween
pumpkin head
walk up
set on
suddenly
trap
climb from

Whether the first n terms and Sn in the arithmetic sequence {an} are written as Sn = an & # 178; + BN (n ∈ n *) (where A.B is a constant)

a(n)=a+(n-1)d,
s(n)=na+n(n-1)d/2=(d/2)n^2 + (a-d/2)n,
A=d/2,B = a - d/2.
s(n)=An^2+bn.
Sn can be written as Sn = an & # 178; + BN, where a = D / 2, B = a - D / 2

Given 2x & sup2; + 5xy-3y & sup2; = 0 and XY ≠ 0, find (2x + 3) / (2x-3y)

2x²+5xy-3y²=0
(x+3y)(2x-y)=0
So x = - 3Y or y = 2x
x=-3y
The original formula = (- 6y + 3Y) / (- 6y-3y) = - 3Y / (- 9y) = 1 / 3
y=2x
The original formula = (2x + 6x) / (2x-6x) = 8x / (- 4x) = - 2

The second coal transportation by car is 28 tons less than that of the first one. The second coal transportation is 0.8 times of that of the first one. How many tons are transported in each of the two times?

Suppose x tons were transported in the first time, then 0.8x tons were transported in the second time
for the first time:
X-0.8X=28
0.2X=28
X=140
The second time:
0.8X=0.8×140=112
A: 140 tons for the first time and 112 tons for the second time
Seeking the best~
I'll answer first. Don't follow me!

How many pairs of vertex angles? How many pairs of complementary angles? How many pairs of apposition angles? How many pairs of internal stagger angles? How many pairs of internal angles on the same side?

N (n-1) pairs of apical angle, internal stagger angle and ipsilateral internal angle

It is known that the function f (x) is defined on the interval (- 1,1), f (1 / 2) = - 1, and if x and Y belong to (- 1,1), f (x) - f (y) = f ((X-Y) / (1-xy))
Let {an} satisfy A1 = 1 / 2, an + 1 = (2An) / (1 + an ^ 2). Let BN = 1 / F (A1) +. 1 / F (an). Find the expression of F (an)
Whether there is a positive integer m, so that for any n belonging to N, it is true that BN is less than (M-8) / 4. If there is, the minimum value of M is obtained; if not, the reason is given

For f (x) - f (y) = f ((X-Y) / (1-xy)), substituting y = x leads to f (0) = 0, substituting x = 0 leads to f (- y) = - f (y) (so it is an odd function) substituting y = x leads to 2F (x) = f (x) - f (- x) = f (2x / (1 + x ^ 2)) discovery and a_ So f (a)_ n+1) = 2f(a_ n) The first term is f (a)_ ...

Physical and chemical properties of water
It needs to be complete and detailed

Water (H2O) is an inorganic substance composed of hydrogen and oxygen. It is a colorless and odorless transparent liquid under normal temperature and pressure. Water is one of the most common substances. It is an important resource for all life including human beings. It is also the most important part of organisms. Water plays an important role in the evolution of life

Formula of cattle grazing problem

1. (number of cattle × days with more grass - number of cattle × days with less grass) / (days with more grass - days with less grass) = amount of new grass per day
2. Head number of cattle × days of grazing - new length of each day × days of grazing = original grass amount of grassland

Given log236 = 1 and log210 = B, log215 can be expressed as a and B?

log2 36=a
log2 6^2=a
2log2 2*3 =a
log2 2 +log 2 3=a/2
1+log2 3=a/2
log2 3 =a/2-1
log2 10=b
log2 2*5=b
log2 2 + log2 5=b
log2 5=b-1
log2 15=log2 3*5=log2 3 + log2 5
=a/2-1 + b-1
=a/2+b-2

Nine tenths of a number is one sixth of 36

This number = 36 × 1 / 6 △ 9 / 10 = 20 / 3