a. B ∈ R, then the equivalent proposition of a square + b square = 0 is

a. B ∈ R, then the equivalent proposition of a square + b square = 0 is

a. B ∈ R, then the equivalent proposition of a square + b square = 0 is a, B ∈ R, a = b = 0

Judge whether the following propositions are true or false and give reasons:
(1) If a is an integer, then a is a rational number
(2) If a is a rational number, then a is an integer

(1) Is a true proposition. Integers belong to rational numbers
(2) Rational numbers include integers and fractions. A may be fractions

How often do you change the water in a swimming pool? How much does it cost?

According to the operator, there is no standard for this problem. A swimming pool water can be used for a month or even a year. Don't worry about the water quality, because the standard swimming pool is equipped with a complete water circulation treatment system, which ensures the water quality to meet the standard through sedimentation, filtration, disinfection, heating and other treatment processes, It's hard for viruses and bacteria to survive. The treated water is the same as the water you just put in. So there's no need to change the water frequently,
The specific cost of a change of water depends on the local water price. I'm a professional swimming pool equipment manufacturer. Such a question is often asked by many operators

Xiaoqiang travels 53 kilometers in 13 hours. According to this calculation, he can travel in 1 hour______ Kilometer, he needs 1 kilometer______ Hours

53 △ 13 = 5 (km / h). 1 △ 5 = 0.2 (H). So the answer is: 5, 0.2

Idiom:_ Hair_ Angle_ Back_ waist
Fillings

It's very rare

The median score was 95 for 2, 85 for 5, 80 for 8, 75 for 8, 70 for 6, and 65 for 1

Median of N numbers:
First, sort the data, and then divide it into the following two cases:
1. If n is even, it is the average of the middle two numbers
2. If n is odd, it is the middle number
In this question, 1 + 6 + 8 + 8 + 5 + 2 = 30. So the median should be the average of the 15th and 16th numbers, that is, (75 + 80) / 2 = 77.5

Find x √ 2x-5 = √ 5x + 1-3, 2x - 5 is inside √, and 5x-1 is inside √, and - 3 is outside √
Find x √ 2x-5 = √ 5x + 1-3
2X - 5 is in √
5x-1 is also in √
-3 outside √
I know the answer is 3 or 7, but who can write the process?

It's OK to square twice
2x-5=5x+1+9-6√(5x+1)
6√(5x+1)=3x+15
2√(5x+1)=x+5
4(5x+1)=x²+10x+25
x²-10x+21=0
(x-3)(x-7)=0

The students read these books interestingly

Students look at these interesting books

How many units is a unit in the tenth? A.10 b.100 c.1000 d.1000
How many units is a unit in the tenth place equal to a unit in the tenth place?
A.10 B.100 C.1000 D.1000
Change option d to 10000

B

Simple calculation of 3.2 × 3.4 15.8 × 3.23.2
Remember to simplify the calculation!

3.2×3.4+15.8×3.2+3.2
=3.2×(3.4+15.8+1)
=3.2×20.2
=3.2×(20+0.2)
=64+0.64
=64.64