Let the common ratio of the equal ratio sequence {an} be - 2, if a1 + A4 + A7 +. + A97 = 5, then A3 + A6 + A9 +. + A99 is equal to Such as the title, if you can also ask experts to write the process in detail, I am more stupid, ha ha

Let the common ratio of the equal ratio sequence {an} be - 2, if a1 + A4 + A7 +. + A97 = 5, then A3 + A6 + A9 +. + A99 is equal to Such as the title, if you can also ask experts to write the process in detail, I am more stupid, ha ha

Let an = A1 * q ^ (n-1), so a1 + A4 + A7 +. + A97 = a1 + A1 * q ^ 3 + A1 * q ^ 6 + a1q^96=a1(1+q^3+q^6+…… +q^96)=5,a3+a6+a9+.+a99=a1q^2+a1q^5+a1q^8+…… a1q^98=a1(1+q^3+q^6+…… +q^96)q^2=5*(-2)^2=20
According to the first equation, calculate A1: put out A1 of each term, and in brackets is the sum of an equal ratio sequence with 1 as the first term and Q ^ 3 as the common ratio, and then bring A1 into the formula! The solution is the same as the first one!
(a1 + A4 + A7 +... + A97) X4 = 5X4 = 20 pay attention to the relationship between serial numbers 1, 3, 4 and 6
Calculation question: (- 4x ^ 2) (3x + 1)
(-4x^2)(3x+1)
=-4x^2*3x-4x^2*1
=-12x^3-4x^2
(-4x^2)(3x+1)
= -4x²(3x+1)
= -12x³ -4x²
：(-4x^2)(3x+1)
=(-4x^2)*3x+(-4x^2)*1
=-12x^3-4x^2
(1) Xiaohong bought 12 more orchids than rose. It is known that the number of orchids is three times that of rose. How many orchids did Xiaohong buy?
(2) If 260 tons are taken out of warehouse A and 60 tons are taken out of warehouse B, the tons of grain stored in warehouse A and warehouse B are equal. How many tons are stored in each warehouse?
(3) Xiao Ming's deposit is three times that of Xiao Gang. Now Xiao Ming withdraws 8500 yuan and Xiao Gang withdraws 500 yuan. The two people's deposits have become the same. How many yuan did Xiao Ming and Xiao Gang have in the past
(4) A's deposit is four times as much as B's. A has 600 yuan more than B's. how many yuan do a and B have?
(5) There are 32 more white rabbits in the farm than grey rabbits. The number of white rabbits is 5 times of grey rabbits. How many white rabbits and grey rabbits are there?
(6) The tonnage of grain stored in warehouse A is three times that of warehouse B. If 80 tons are taken out of warehouse A and transported into warehouse B, the tonnage of grain stored in warehouse A and warehouse B is exactly the same. How many tons of grain were there in warehouse A and warehouse B?
This question is for children. Children are only three years old in primary school. Friends who answer questions should try not to use the formula with X. it's better to help them with simple and easy to understand answers
(1) Xiaohong bought 12 more orchids than Chinese rose. It is known that the number of orchids is 3 times that of Chinese rose. How many orchids and Chinese rose did Xiaohong buy? The number of orchids is 3-1 = 2 times that of Chinese rose. The number of Chinese rose is 12 / 2 = 6. The number of orchids is 6 × 3 = 18 or 6 + 12 = 18
(1) 12 ÷ (3-1) = 6 pieces, 6 * 3 = 18 pieces
A: Xiaohong bought 6 orchids and 18 roses
(2) (260-60) / (3-1) = 100 tons (b granary)
100 * 3 = 300 tons (a granary)
(3) (8500-500) / (3-1) = 4000 yuan (Xiaogang)
4000 * 3 = 12000 yuan Xiaoming
(4) 600 ÷ (4-1) = 200 (b)
200 * 4 = 800 (a)
(5) ... unfold
(1) 12 ÷ (3-1) = 6 pieces, 6 * 3 = 18 pieces
A: Xiaohong bought 6 orchids and 18 roses
(2) (260-60) / (3-1) = 100 tons (b granary)
100 * 3 = 300 tons (a granary)
(3) (8500-500) / (3-1) = 4000 yuan (Xiaogang)
4000 * 3 = 12000 yuan Xiaoming
(4) 600 ÷ (4-1) = 200 (b)
200 * 4 = 800 (a)
(5) 32 ÷ (5-1) = 8 (grey rabbit)
8 * 5 = 40 (white rabbit)
(6) (80 + 80) / (3-1) = 80 tons (warehouse b)
80 * 3 = 240 tons
1. 12 / (3-1) = 6, 6 * 3 = 18, rose 6, orchid 18. (the extra part is double the relationship)
2. (260-60) / (3-1) = 100100 * 3 = 300
3. The same as above, (8500-500) / 2 = 4000 * 3 = 12000
4、600/（4-1）=200，200*4=800
5、
It's all a kind of... Unfolding
1. 12 / (3-1) = 6, 6 * 3 = 18, rose 6, orchid 18. (the extra part is double the relationship)
2. (260-60) / (3-1) = 100100 * 3 = 300
3. The same as above, (8500-500) / 2 = 4000 * 3 = 12000
4、600/（4-1）=200，200*4=800
5、
It's all one type. Let me teach you some ideas
N = (b) - A, that's 1 times. Put it away
1: Because there are 12 more orchids than roses, the number of known orchids is three times that of roses
So the extra 12 are twice as many as the roses
There are 12 / 2 roses = 6 and 6 * 3 orchids = 18
2: The tonnage of grain stored in warehouse A is three times that of warehouse B. If 260 tons are taken out of warehouse A and 60 tons are taken out of warehouse B, the tons of grain stored in warehouse A and warehouse B are equal
If each bin is put back to 60
That is 260-60 = 200, twice as much as warehouse B
So warehouse B has 200 / 2 = 100 tons
A warehouse has 100 * 3 = 30... Expansion
1: Because there are 12 more orchids than roses, the number of known orchids is three times that of roses
So the extra 12 are twice as many as the roses
There are 12 / 2 roses = 6 and 6 * 3 orchids = 18
2: The tonnage of grain stored in warehouse A is three times that of warehouse B. If 260 tons are taken out of warehouse A and 60 tons are taken out of warehouse B, the tons of grain stored in warehouse A and warehouse B are equal
If each bin is put back to 60
That is 260-60 = 200, twice as much as warehouse B
So warehouse B has 200 / 2 = 100 tons
A warehouse has 100 * 3 = 300 tons
3: For example, the income of xiaogangyou (8500-500) / 2 = 4000 yuan
Xiaoming has 4000 * 3 = 12000 yuan
4: As the first question
B has 600 / 3 = 200 yuan
A has 200 * 4 = 800 yuan
5. From the first question
There are 32 / 4 = 8 grey rabbits
There are 8 * 5 = 40 white rabbits
6: The tonnage of grain stored in warehouse A is three times that of warehouse B. If 80 tons are taken out of warehouse A and transported into warehouse B, the tonnage of grain stored in warehouse A and warehouse B is exactly the same
That is, a is 80 + 80 more than B = 160 tons
According to the first question
B: 160 / 2 = 80 tons
A has 80 * 3 = 240 tons
It's very simple. 12 * 3 is orchid. Rose is 12. 12 * 3 = 36 orchids
How is a type of problem, set the less one for X, a formula will come out
(1) If x roses, 3x orchids, 3x-x = 12, x = 6, 6 × 3 = 18 orchids. Therefore, there are 18 orchids and 6 roses.
(2) Let B be x tons, so a be 3x tons. X-60 = 3x-260. X = 100 tons, a is 100 × 3 = 300 tons. So 300 tons for a and 100 tons for B.
(3) If Xiaogang's deposit is x yuan, Xiaoming's deposit is 3x yuan. 3x-8500 = x-500, x = 4000 yuan, Xiaoming deposit is 4000 × 3 = 120 yuan
(1) If x roses, 3x orchids, 3x-x = 12, x = 6, 6 × 3 = 18 orchids. Therefore, there are 18 orchids and 6 roses.
(2) Let B be x tons, so a be 3x tons. X-60 = 3x-260. X = 100 tons, a is 100 × 3 = 300 tons. So 300 tons for a and 100 tons for B.
(3) If Xiaogang's deposit is x yuan, Xiaoming's deposit is 3x yuan. 3x-8500 = x-500, x = 4000 yuan, Xiaoming deposit is 4000 × 3 = 12000 yuan. So Xiaoming deposits 12000 yuan and Xiaogang 4000 yuan.
(4) Let B deposit X Yuan, then a is 4x yuan. 4x-x = 600, get x = 200 yuan, Jiacun 200 × 4 = 800 yuan. So a deposit 800 yuan, B deposit 200 yuan.
(5) If the number of grey rabbits is x, the number of white rabbits is 5x. 5x-x = 32, x = 8, the number of white rabbits is 40. So there are 40 white rabbits and 8 grey rabbits.
(6) If there is x tons of grain stored in warehouse B, the grain storage in warehouse A is 3x tons. 3x-80 = x + 80, x = 80 tons, a warehouse is 80 × 3 = 240 tons. So there are 240 tons of grain in warehouse A and 80 tons in warehouse B. Put it away
It is known that {an} is an equal ratio sequence with a common ratio of 1 / 2 if a1 + A4 + A97 = 200 find A3 + A6 + The value of A99
A is followed by a subscript
a3=a1*q^2,a6=a4*q^2,.,a99=a97*q^2;
So A3 + A6 + a99=（a1+a4+…… a970*q^2 =200 *(1/2)^2=50
Calculate 1 / (x ^ 2-3x + 2) + 1 / (x ^ 2-5x + 6) + 1 / (x ^ 2-4x + 3)
=1/(x-2)(x-1)+1/(x-2)(x-3)+1/(x-3)(x-1)
=(x-3+x-1+x-2)/(x-1)(x-2)(x-3)
=3(x-2)/(x-1)(x-2)(x-3)
=2/(x-1)(x-3)
Original formula = 1 / (x-1) (X-2) + 1 / (X-2) (x-3) + 1 / (x-1) (x-3) = [(x-3) + (x-1) + (X-2)] / (x-1) (X-2) (x-3) = 3 / (x-1) (x-3)
Uncle and second uncle tied up the same number of lanterns to sell. Uncle sold 4 lanterns and second uncle sold 2 lanterns. The second uncle's remaining lanterns were three times as many as his uncle's. how many lanterns did Uncle and second uncle tie up?
You can't use the equation_ (:з」∠)_
(3 * 4-2) / (3-2) = 5
Five... A total of six were sold, and the second uncle was three times as much as the first uncle, that is, the remaining four times...
The number of uncles left: (4-2) / (3-1) = 1
First uncle and second uncle: 1 + 4 = 5 each
A total of six were sold, and the second uncle was three times as much as the first uncle, that is, the remaining four times...
If there is one uncle left, then there are three uncles left. There are 1 + 4 = 5 eldest uncles and 3 + 2 = 5 second uncles. It is consistent with the title of "tie the same number of lanterns".
If there are two uncles left, then there are six uncles left. 2 + 6 = 2 + 6 = 8. It is not consistent with the title of "tie the same number of lanterns".
If there are three uncles left, then there are three uncles left. There are 3 + 4 = 7 eldest uncles and 9 + 2 = 11 second uncles. It is not consistent with the title of "tie the same number of lanterns".
If there are four uncles left, then there are four uncles left
If there is one uncle left, then there are three uncles left. There are 1 + 4 = 5 eldest uncles and 3 + 2 = 5 second uncles. It is consistent with the title of "tie the same number of lanterns".
If there are two uncles left, then there are six uncles left. There are 6 great uncles and 8 second uncles. It is not consistent with the title of "tie the same number of lanterns".
If there are three uncles left, then there are three uncles left. There are 3 + 4 = 7 eldest uncles and 9 + 2 = 11 second uncles. It is not consistent with the title of "tie the same number of lanterns".
If there are four uncles left, then there are 12 uncles left. There are 4 + 4 = 8 eldest uncles and 12 + 2 = 14 second uncles. It is not consistent with the title of "tie the same number of lanterns".
…………
It can be seen from the above that only if there is one uncle left and three uncles left, the original title is true. So uncle and second uncle used to tie five lanterns each.
Thank you very much
Please put it away
(4-2 / 3) divided by 2 / 3
Second uncle's remaining lanterns: (4-2) / (3-1) = 1 (lanterns) second uncle's lanterns: 1 + 2 = 3 (lanterns) first uncle's lanterns: 1x3 + 4 = 7 (lanterns)
In the equal ratio sequence {an}, the common ratio q = 1 / 2, and A3 + A6 + A9 +Then a 1 + a 2 = a 1 + a 2 + a 2 = a 2 + a 2 + a 3 + a 2 = a 2 + a 2 + a 3 + a 2 + a 3 + a 2 + a 3 + a 2 + a 3 + a 2 + a 3 + a 2 + a 2 + +a99=
a6/a3=q^3q9/q6=q^3…… So A3, A6 Q = 3 + AQ = 3 '/ AQ = 3' / AQ = 3 '/ AQ = 3' / AQ = 3 '/ AQ = 3' / AQ = 3 '/ AQ = 3' / AQ = 3 '/ AQ = 3' / AQ = 3 '/ AQ = 3' / AQ = 3 '/ AQ = 3' +a99=a3*(1-q'^33)/(1-q')=a3*[1-(q^3)^33]/(1-1/8)=a3(1-q^99)/(7/8)=60a3(1-q^99)=60*7/8a1*(1-q^99)=(a3/q^2)(1-q^99)=4...
4X ^ 3 - (3x ^ 2 + 5x-2) + 2 (3x + 2 / 3x ^ 2-2x ^ 3) - 1, where x = 2007
4x-(3x+5x-2)+2(3x+3/2x-2x)-1 =4x-3x-5x+2+6x+3x-4x-1 =x+1 =2007+1 =2008
The rice stored in warehouse A is three times as much as that in warehouse B. If 850 kg is transported from warehouse A and 50 kg is transported from warehouse B, the rice stored in the two warehouses is equal?
We haven't learned unknowns yet. We can't use XY
Draw a line diagram, will be very clear, difference times ask
B: (850 + 50) / (3-1) = 400 (kg)
A: 400 × 3 = 1200 (kg)
400kg
Suppose: a x, B y
X=3Y
X-850=Y-50
A: x = 1200, y = 400
(850-50) / (3-1) = 400kg
A: there was 400 kg of rice in warehouse B