This year, my grandfather's age is six times that of Xiao Ming. In a few years, my grandfather's age will be five times that of Xiao Ming. In a few years, my grandfather's age will be four times that of Xiao Ming

This year, my grandfather's age is six times that of Xiao Ming. In a few years, my grandfather's age will be five times that of Xiao Ming. In a few years, my grandfather's age will be four times that of Xiao Ming

Suppose grandfather is x years old, then Xiao Ming is y years old. The first year passed a, and the second year passed B, x = 6yx + a = 5 (y + a) x = 5Y + 4ax + A + B = 4 (y + A + b) x = 4Y + 3A + 3b solution x = 24a, y = 4A, B = 5A3 according to the actual a = 3, B = 5Y = 12x = 72 A: grandfather is 72 years old

There are a series of formulas: 2 + 4, 8 + 5, 14 + 6, 20 + 7 If every number is arranged in a regular way, then the 99th formula is______ +______ ．

According to the analysis, the 99th formula is: (6 × 99-4) + (99 + 3) = (594-4) + 102 = 590 + 102

On the formula of mathematical calculation and summation
How to find the square of a + the square of B?
Calculation, the answer a few days and then add points, now no points
1.（2×2+4×4+6×6+…… +100×100）-（1×1+3×3+5×5+…… +99×99)
-------------------------------------------------------------------
1+2+3+…… +10+9+8+…… +1
2.1 1 1 1 1
------ + --------- + -------- +…… + ------------ + -----------
3×1 4×2 5×3 1999×1997 2000×1998
The second question is three times one and four times one half six

1) Upstairs is 4-1 + 16-9 + 36-25. = 3 + 7 + 11 + 15 +... + 199 = 202 * 50 / 2 = 5050, downstairs is 100, so it is 50.5.2) 1 / N (n + 2) = 0.5 [1 / n-1 / (n + 2)]. So the original formula = 0.5 [1-1 / 3 + 1 / 2-1 / 4 + 1 / 3-1 / 5. = 0.5 [1 + 1 / 2-1 / 1999-1 / 2000]. Do you have any formula for A2 + B2

Beijing Normal University Edition Grade 8 Volume 2 mathematics Chapter 1 review questions~~~~~~~~~~

Untitled

The characteristics of the sample estimate the numerical characteristics of the population (15:20:5:54)
A and B buy grain at the same store at the same time (assuming that the unit price of grain is different each time). A buys grain a kg each time, and B buys grain a yuan each time. Suppose that the price of grain purchased by a and B for the first time is x yuan per kilogram, and the price of grain purchased for the second time is y yuan per kilogram, (1) Find out the average price of grain purchased twice by Party A and Party B respectively. (2) whose average price of grain purchased twice is lower?

A (AX + ay) / 2A = (x + y) / 2
B 2A / (A / x + A / y) = 2XY / (x + y)
A-B = (X & sup2; + Y & sup2; - 2XY) / 2 (x + y) > 0
B low

Thoughts on 2000 words in "flying gazelle"

The author of the novel is Shen Shixi, the famous King of animal novels. Reading his book makes my blood boil. It seems that I am experiencing the story myself. When I read the story of the story, it seems that I am trying to escape and jump together with the gazelle

The answer in the valley

Answers to supplementary exercises in primary school Chinese Lesson 17, the answer in the valley
1
The tent destroyed the big branches
Intact, green and straight
2
1. Take on
2. Uncovering
3. It's not That is It's not But
3
1、qū tán
2. Explanation
3. Face up to difficulties and pressures, face them and make concessions
4. Enlighten people in the face of adversity and pressure, not only to dare to fight, but also to learn to retreat, to retreat, can better survive and develop
four
1. Seepage erosion collapse
2. Yes, many hidden dangers exist inadvertently. We should face every little hidden danger carefully
I typed it word by word
Please! Can you give me the best?
My hands are so sore

4X = 20 / 3 + 16, how to solve the equation

4x=20/3+16
4x=68/3
x=68/3÷4
x=17/3

How to write 7.3 × 0.99 with simple operation?

7.3x0.99
＝7.3x（1－O.O1）
＝7.3x1－7.3x0.01
＝1－0.073
＝0.927

The lamp factory is going to use the iron sheet to process the conical lampshade, in which the radius of the cone bottom circle is 6 π cm, and the bus length is 15cm. It is known that the material loss rate is 10% in the process of processing lampshade, so the actual iron sheet area required for processing 100 such lampshades is (excluding joints)______ cm2．

∵ the radius of the cone bottom circle is 6 π cm, and the bus length is 15cm. According to the formula of the side area of the cone: S = π RL = π × 6 π × 15 = 90cm 2, ∵ in the process of processing lampshade, the material loss rate is 10%, ∵ when processing 100 such lampshade, the actual iron sheet area required is: 100 × 90 △ 1-10% = 10000cm 2, so the answer is: 10000