If the variable has been correctly defined and assigned, the expressions in accordance with C language syntax are a = a + 7; B a = 7 + B + C, a + + C int (12.3% 4) d a = a + 7 = C + B

If the variable has been correctly defined and assigned, the expressions in accordance with C language syntax are a = a + 7; B a = 7 + B + C, a + + C int (12.3% 4) d a = a + 7 = C + B

A = a + 7; / / does not match. This is not an expression, but a statement
B a = 7 + B + C, a + + / / Yes, this is a comma expression
C int (12.3% 4) / / does not match, 12.3 cannot do% operation
D a = a + 7 = C + B / / inconsistent, a + 7 cannot be left
Conclusion: C is correct

If the variable has been correctly defined and assigned, the following expression in line with C language syntax is (). A.A: = B + 1 Ba = b = C + 2 c.int 18.5% 3 D.A = a + 7

The first one can't be added after it: the third variable is wrong, it's a constant. The fourth one should be a + = a
The second is right

If the variable has been correctly defined and assigned, the following expressions in line with C language syntax are () (1 point) a, a: = B + 1 B, a = b = C + 2 C, int 18.5% 3
If the variable has been correctly defined and assigned, the following expression in line with C language syntax is (). (1 point)
A、a:=b+1 B、a=b=c+2
C、int 18.5%3 D、a=a+7=c+b

": =" in a is not a recognized operator, so it is wrong;
B is right, equivalent to: B = C + 2; a = B; (assignment from right to left);
C: Wrong, either define the variable: int a = 18.5% 3, or cast the data type: (int) 18.5% 3; int 18.5% 3, which is neither fish nor fowl;
There can be no expression on the left side of the "d" = "sign. You can't assign a value to an expression, so D is wrong,

In the acute angle △ ABC, if the side length of angle B is 10, the area of △ ABC is 10, and the radius of circumscribed circle R is 13, then the perimeter of △ ABC is 10______ ．

According to the sine theorem, bsinb = 2R, B = 10, r = 13, SINB = 513, CoSb = 1213, area of ∵ ABC = 10, AC = 52, then CoSb = 1213 = A2 + C2 − b22ac = A2 + C2 − 1022 × 52

Given that x > 1, compare the square of x minus one with twice the square of x minus 2x

(x^2-1)-(2x^2-2x)
=-x^2+2x-1
=-(x-1)^2
Because x > 1
So - (x-1) ^ 2

Xiao Ming passed by a building and looked at the glass curtain wall from the side. He found that the flagpole in front of the building was misplaced in the glass curtain wall

Glass curtain wall in the installation of flatness has a certain deviation requirements, as long as within the standard deviation, are accepted

Suitable for the fourth grade of primary school science small production practice I urgently need

Fish tank water exchanger material: 250ml empty coke bottle, about one meter long soft rubber tube (inner diameter is about 7mm), universal glue make two eyes on the cap of coke bottle (slightly smaller than the tube), cut the tube into 70cm and 30cm ends, respectively insert into the cap for 1cm, glue the joint with universal glue, screw on the cap

Given x ^ 2-5x + 1 = 0, find the value of 1 / X of X-X

Solution
x²-5x+1=0
Divide both sides by X to get:
x-5+1/x=0
∴x+1/x=5
(x-1/x)²=(x+1/x)²-4=5²-4=21
∴x-1/x=±√21

The following is the plan of the school basketball court drawn according to the scale of 1:1000. Please measure and calculate the actual length and width of the court?
What's the floor area? A standard basketball court is 28 meters long and 15 meters wide. Is it standard?

Sorry! The original question is incomplete (no picture), can't answer directly
Please review the original question and complete it when asking. Thank you!

I need two! 50 words

One day, a group of young people came to the "Plato's school" in the shade of the suburb of Athens. The door of the school was closed, and there was a wooden sign hanging on the door, which said: "those who don't know mathematics are not allowed to enter." this was the rule set by Plato himself in order to let the students know that he attached great importance to mathematics, Some people are thinking that it's because I don't know mathematics that I want to come here for advice. If I do, what else can I do here? Just as people look at each other, I don't know whether to retreat or advance, Euclid comes out of the crowd. He straightens his clothes, looks at the sign, and resolutely pushes the gate of the school, He went in without looking back
There is such an interesting story about Archimedes. It is said that king syracuhnon asked the craftsman to make a pure gold crown for him. After the crown was made, the king suspected that the craftsman had mixed the fake with the gold crown, but the gold crown was as heavy as the pure gold he had given to the Goldsmith. Did the craftsman make trouble? He wanted to test the authenticity but could not destroy the crown, It also made the ministers look at each other
Later, the king asked Archimedes to test it. At first, Archimedes thought hard and couldn't get to the point. One day, he went to the bath. When he sat in the bath, he saw the water overflowing and felt his body gently pulled up. Suddenly, he realized that the proportion of golden crown could be determined by measuring the water discharge of solids in the water. He jumped out of the bath excitedly and even couldn't care about his clothes, Yelling "Eureka! Eureka!" (fureka, meaning "I know")
After further experiments, he came to the palace. He put the crown and the same weight of pure gold in two pots full of water. Comparing the water overflowing from the two pots, he found that the water overflowing from the basin where the crown was placed was more than that from the other basin. This shows that the volume of the crown is larger than that of the pure gold of the same weight, so it proves that other metals are mixed into the crown
The significance of this experiment is far greater than finding out that the goldsmith cheated the king. Archimedes found the law of buoyancy: the buoyancy obtained by an object in the liquid is equal to the weight of the liquid he discharged. Until now, people still use this principle to calculate the specific gravity of objects and determine the ship's carrying capacity