Xiaogang is 1 / 5 heavier than Xiaohua. Xiaohua's weight is 35 kg. Xiaoming is 1 / 7 lighter than Xiaohua. How many kg do they use the equation to solve

Xiaogang is 1 / 5 heavier than Xiaohua. Xiaohua's weight is 35 kg. Xiaoming is 1 / 7 lighter than Xiaohua. How many kg do they use the equation to solve

Let Xiao Gang's weight be x and Xiao Ming's weight be y
（X-35）/35=1/5
（35-Y）/35=1/7
The solution is as follows
X=42,Y=30
A: Xiaogang weighs 42 kg and Xiaoming weighs 30 kg

Xiaohua's weight is 35 kg. Xiaogang is one fifth heavier than Xiaohua, and Xiaoming is one seventh lighter than Xiaohua. How many kg are Xiaogang and Xiaoming?

Xiaogang = 35 × (1 + 1 / 5) = 42kg
Xiaohua = 42 △ 1 / 7 = 42 × 7 / 6 = 49kg

The greatest common factor and the least common multiple of 12 and 72?

12 = 2 × 2× 3
— — —
72 = 2 × 2× 3× 2× 3
— — —
The greatest common factor of 12 and 72 is 12
The least common multiple of 12 and 72 is 72

2 x-3 + 3 2x + 1 = 6 x + 5

2 x-3 + 3 2x + 1 = 6 x + 5
Multiply both sides by six
3x-9 + 4x+2 = x +5
6x = 12
x =2

Judge the proposition. "If a > 0, then a & # 178; > a" is true or false. If it is true, please prove it; if it is false, please give a counterexample

Counter evidence: if it is true, then a & # 178; - a > 0 means a (A-1) > 0
Because a > 0
So a > 1
So a > 1 is not consistent with a > 0
As long as it's 0

Sum of equal ratio sequence divided by equal difference sequence
An = 2 ^ n / (n + 1), find SN
An = (n + 2) * 2 ^ n / (n + 1), find SN
The second question is simplified to the first one. Write down the process of seeking SN. It is said that the wrong term is used to subtract. Alas, can I. come on, great Xia!
Forget to say, reward! Can't you type something to the point? How to answer is irrelevant. Go back to the second floor, divide n + 2 into N + 1 + 1, and then move the term. SN is sum of 2 ^ n + 2 ^ n / (n + 1). Just tell me how to sum the first question. It's meaningless after today

You should have some mistakes in the first few steps, otherwise you can't do it. There's no law in advanced mathematics

F (x) = x ^ 3 + MX ^ 2 - m ^ 2x + 1, with a maximum value of 9, find M

Derivation:
f'(x)=3x^2+2mx-m^2=0
The solution is x = m / 3 or - M
And f '' (x) = 6x + 2m

1. The side length of a cube is 0.1M (expressed by scientific notation)
(1) What's the surface area of the cube?
(2) What's the volume of this cube?
2. Express the following data by scientific counting method
0.00408,15000,0.00000087,105000000
4. How many significant numbers are they accurate to?
58.9 ,3.695,5.0,1.50x10³

1. The side length of a cube is 0.1M (expressed by scientific notation)
(1) What is the surface area of the cube? Surface area = 6 × (0.1 × 0.1) = 6 × 10 ^ (- 2) (M2)
(2) What is the volume of this cube? Volume = 0.1 × 0.1 × 0.1 = 1 × 10 ^ (- 3) (cubic meter)
2. Express the following data by scientific counting method
0.00408,15000,0.00000087,105000000
0.00408=4.08×10^(-3)
15000=1.5×10^4
0.00000087=8.7×10^(-7)
105000000=1.05×10^8
4. How many significant numbers are they accurate to?
58.9 ,3.695,5.0,1.50x10³
58.9 to the tenth, with three significant digits
695 to the thousandth, with four significant digits
5.0 is accurate to the tenth, with two significant digits
50 x 10 & sup 3; accurate to ten digits with three significant digits

The number of columns arranged regularly: 2,4,6,8,10,12 Each of its terms can be expressed by the formula 2n (n is a positive integer)
The number of columns arranged regularly: 2,4,6,8,10,12 Every term of it can be expressed by the formula 2n (n is a positive integer). There is a regular column of numbers: 1, - 2,3, - 4,5, - 6,7, - 8 (1) Calculate the sum of the first 2011 numbers.

Two in a group is - 1
-1*2010/2+2011=1006

The first line of n-order determinant is x a A the first line is a x a A line n is a x

This is typical of every line and is the same
It's to add all of them to the first line, then bring up the number, and subtract the first line from each line starting from the second line
D (n) = [x + (n-1) a] (x-a) to the (n-1) power