If a and B are rational numbers and | a | + | B | = 0, then () A. A and B are opposite numbers, B. A = b = 0C. A and B have opposite signs, and the value of d. A and B does not exist

If a and B are rational numbers and | a | + | B | = 0, then () A. A and B are opposite numbers, B. A = b = 0C. A and B have opposite signs, and the value of d. A and B does not exist

∵|a | + |b | = 0, ∵ a = b = 0

If a and B are non-zero rational numbers, what is the value of a | a | + B | + ab | ab |?

When a ＞ 0, B |a |a || + B | B | B || + ab | ab || ab | = 1 + 1 + 1 + 1 + 1 = 3; when a ＞ 0, B ＜ < 0, a |a |a | + B || + ab |||| + ab | | | |b 124\124\\\\\\\\\\\\124\\ + 1 = - 1

Given that a, B and C are non-zero rational numbers, can you find the value of | a | / A + | B | / B + | C | / C?
On the division of rational numbers~

This question mainly examines the definition of absolute value, that is, according to a, B, C positive and negative, remove the absolute value sign
|a|/a+|b|/b+|c|/c
A. B, C can be three positive = 3
It can be two positive and one negative = 1
Can be two negative and one positive = - 1
Can be triple negative = - 3

Let A.B.C be a non-zero rational number, let A.B.C be a non-zero rational number, | a | + a = 0, | ABL = AB, | C | - C = 0, simplify | B | - | a + B | + | C-B | + | a-c |

a. B. C is a nonzero rational number,
|A | + a = 0, indicating that a ≤ 0;
|ABL = AB, B ≤ 0;
|C | - C = 0, indicating that C ≥ 0;
Therefore:
|b|-|a+b|+|c-b|+|a-c|
=-b+(a+b)+(c-b)+(c-a)
=2c-b

It's better to answer specifically
Give me all the useful formulas. If I'm satisfied, I'll go after 10 more~

G = mg, where G is the gravity of the object, M is the mass of the object, g = 9.8n/kgp = f / s, where p is the pressure, f is the pressure, s is the stressed area (the common contact area of the two objects in extrusion). 1pA = 1n / m ^ 2 cube, cuboid, cylinder, prism and other objects with uniform thickness above and below are placed on the horizontal table

A vertical spring is connected with a thin plate with mass m, on which a wooden block with mass m is placed. Now the whole device moves harmonically in the vertical direction with amplitude A. if the wooden block is required not to separate from the board in the whole process, what is the spring stiffness coefficient K?

If the board moves to the highest point and does not break away, the spring may be in two states: invisible change state and compression state. If it just breaks away, the spring will be invisible change at this time, and the acceleration of M and M is g. at this time, the restoring force of the system is f = (M + m) g, so the elastic force of the spring at the equilibrium position is Ka = (M + m) g, k = g. if the spring is in compression state, the restoring force of the system at the highest point is f'ka, then K< So K ≤ G

How much a is 1kW?

Power = voltage x current

Using a balance and a spring scale to weigh the same object on the earth and the moon respectively, the result is satisfactory
A the results of weighing with balance are the same, but the results of weighing with spring scale are different
B. No.. Phase (omitted as above)
C the results of weighing with balance and spring scale are the same
D. Different

The weight of the scale is equal on the earth and the moon
The spring scale weighs weight, which is different from that on the earth and the moon
So choose a

What is the relationship between the perimeter C of a square and its area s__ Where the constant is__ The variable is___

C = 4 radical s

Two objects Ma and MB of the same size are placed on a smooth horizontal plane with a spring between them. Pull Ma to the left with F1 and MB to the right with F2. F1 > F2 is used to calculate the spring force
The answer I got was (F1-F2) / 2, but it was wrong,

The spring force is F1
It can be understood in this way, because two objects are placed on a smooth horizontal plane, we can see that two objects do uniform acceleration motion on the horizontal plane, and the combined external force is F1-F2. The acceleration of two objects is a = (F1-F2) / m, and it is not difficult to think out that the acceleration of MB is also a = (F1-F2) / m
If the spring tension is f, then (f-f2) / M = a
Find f = F1