The ratio of 1 / 13 to 3 / 5

The ratio of 1 / 13 to 3 / 5

1 in 13: 3 in 5
=1 / 13 × 65: 3 / 5 × 65
=5:39
=5/39

26 decimeters: 13 / 15 meters

26 decimeters: 13 out of 15 meters
=26:130/15
=26:26/3
=3:1
=3

What is the sum of a decimal natural number N and its constituent natural numbers 2011

1991

① The solution set of inequality (1-A) > 2 about X is XB, then A. half a + b > B
③ . solve inequality: | 2-3x | ≥ 2

1. When a = 1, the left side of the inequality is 0 and the right side is 2, so a is not equal to 1;
When a > 1, 1-a1
2. A - (. Half a + b) = (a-b) / 2 because a > b, so A-B > 0, that is, a - (. Half a + b) > 0,
That is, a > half a + B;
In the same way: a + b > B

What does 0.5 * 12 mean
What does 12 * 0.5 mean?

What's the sum of 12 0.5's

The speed of the earth's revolution around the sun is about 1.1 * 10 to the fifth power km / h, and the propagation speed of sound in the air is about 340 m / s, which is a comparison of the two speeds
The size of the
2. A day has 8.64 * 10 quartic s, and a year is calculated by 365 days. How many seconds are there in a year (expressed by scientific counting method)?
3. (1) calculate the second power of 0.1, the second power of 1, the second power of 10, and the second power of 100. Observe these results. When the decimal point of the base moves one place to the left (right), what is the rule of the decimal point of the square?
(2) Calculate the third power of 0.1, the third power of 1, the third power of 10, and the third power of 100. Observe these results. When the decimal point of the base number moves one place to the left (right), what is the rule of the decimal point of the cubic number?
(3) Calculate the fourth power of 0.1, the fourth power of 1, the fourth power of 10, and the fourth power of 100. Observe these results. When the decimal point of the base number moves one place to the left (right), what is the movement rule of the decimal point of the fourth power number?

How many seconds does a year have in 365 days? 3. (1) calculate the second power of 0.1, the second power of 1, the second power of 10, and the second power of 100. Observe these results. When the decimal point of the base number moves one place to the left (right), what is the shift of the decimal point of the square number

Answers to questions 9 and 10 on page 37 of mathematics PEP

The first question is multiplied by X (x + 1) and (2x + 5) at the same time, and then calculated slowly. The ninth question on page 37 is to set the efficiency of farmers as X

In the plane rectangular coordinate system, the coordinates of vertex a of triangle ABO are (1,2), O is the origin of coordinates, and the area of triangle ABO can be calculated with respect to y axis between point B and point a

The word "symmetry" seems to be missing from the title
This triangle is an inverted triangle with the vertex at O and the base a and B at (1,2) and (- 1,2) respectively
Bottom edge AB length 2 - (- 1) = 2
The height is the distance from AB to o, which is the ordinate 2 of A
So area = 2 * 2 / 2 = 2

Simple calculation. 9 / 25 × 17 / 26 + 13 / 25 × 7 / 26

9/25×17/26+13/25×7/26
=1／25×1／26×（9×17＋13×7）
=1／25×1／26×（153＋91）
=1／25×1／26×244
=1／25×1／13×122
=122／325
This is the simplest way!

Basic calculation of chemical reaction rate
Under certain conditions, the reaction N2 + 3h2 = reversible = 2nh3 was carried out in a 2L closed container, and the mass of ammonia increased by 1.7g in 5min,

Sure enough, it's very basic
nNH3=1.7/17=0,1mol
vNH3=0.1/2/5=0.01mol/(L.min)