How many jin is one liter of water?
two
How many grams of water is two liters of water?
The density of water is 1 gram per cubic centimeter, 2 liters equals 2000 cubic centimetres, so it's 2000 grams
If the three sides of a triangle are a, B, C and satisfy A4 + B4 + C4 = a2b2 + b2c2 + c2a2, the triangle is equilateral
A 4 + B 4 + C 4 = A 2B 2 + B 2C 2 + C 2A 2, the left and right sides of a 4 + B 4 + C 4 = A 2B 2 + B 2C 2 + C 2A 2 are all × 2, which is written in the form of complete square: (a 2-B 2) 2 + (b 2-C 2) 2 + (C 2-A 2) 2 = 0, ∵ a, B, C are the three sides of the triangle respectively, ∵ a, B, C are nonnegative, ∵ a 2-B 2 = 0, B 2-C 2 = 0, C 2-A 2 = B 2, C 2 = a 2 ∵ a = b = C, the triangle is equilateral triangle
Choose 9 numbers from 1 to 9 (repeatable), and the sum is equal to 55. Is there a formula to calculate?
Thank you for listening to the wind on the screen, but do you have any specific formula or technique?
Yes,
Obviously, the number of [9-81] can be obtained by adding 9 numbers between 1-9
1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 = 9 is the template,
When the components of 55-9 = 46 are allocated to the positions of 1, each allocation method can get different addition methods, such as
Try to average 6 + 6 + 6 + 6 + 6 + 6 + 6 + 6 + 6 + 6 + 7 = 55,
Try to add odd number 1 + 3 + 5 + 7 + 9 + 7 + 7 + 7 + 9 = 55,
Try to add even number 2 + 4 + 6 + 8 + 8 + 8 + 8 + 8 + 3 = 55,
Solve the equations 4x-3y = - 4.2 X-Y = 2
There should be a process
4x-3y=-4 ①
x/2-y=2 ②
① - 2 * 8
5y=-20
y=-4
Substituting in (2)
x/2-(-4)=2
x/2=-2
x=-4
So x = - 4, y = - 4
Simple calculation of 17 times 5 of 9 and 19
Simple calculation
(1) Nine and nineteen seventeen times five
(2) 14 out of 99 and 25 times minus 5
And tell me why
The first, (10-2 / 19) X5 = 50-10 / 19 = 49 + 9 / 19
The second, (100-11 / 25) x (- 5) is the same as above
There's no reason. It's just like this. It's easy to make up a good number
3 ^ 2-1 ^ 2 = 8 * 1 5 ^ 2-3 ^ 2 = 8 * 2 7 ^ 2-5 ^ 2 = 8 * 3. Question: 1. What law do you find from the above equation? Express it in algebraic form
2. Calculate from the above rule: 2001 ^ 2-1999 ^ 2
(2n+1)^2-(2n-1)^2=8n
Simplify the formula on the left, as follows
(2n+1)^2-(2n-1)^2=4n^2+4n+1-4n^2+4n-1=8n
(35-12 / 6, 49 + 63-30 / 20, 77 + 91-56 / 42, 105) - 1 and 3 / 8] divided by 1 / 8
[(35-12 / 6, 49 + 20, 63-30, 77 + 42, 91-56, 105) - 1 and 3 / 8] / 1 / 8
=[6-1 / 6-4-1 / 12 + 3 + 3 / 20-2-17 / 30 + 2 + 1 / 6-2-1 / 8-1 and 1 / 8] × 8
=【2-1/12+3/20-17/30-1/4】×8
=5/4×8
=10
For a triangle, if the base increases by 2 cm, the height remains unchanged, and the area increases by 12 square cm; if the height decreases by 3 cm, the base remains unchanged, and the area decreases by 12 square cm
Let the height of the original triangle be h cm and the bottom be a cm, (a + 2) × h △ 2-ah △ 2 = 12 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 2H = 12 × 2 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp
Solving equation 36 + x-2x = 18
36-x=18