7th grade math and English problems, 7th grade math problems

Mathematics: In rational numbers, a decimal is a fraction, and a fraction is not a decimal (reason:

All numbers are divided into rational numbers, irrational numbers, rational numbers, and rational numbers, which are divided into integers and fractions, and those that do not have a decimal point are integers, except for these integers, everything else is a fraction, including the root number (the root number that cannot be opened), the fraction and so on are all fractions, so the decimal is only a part of the fraction.

It's not a decimal that is a fraction, remember, the concept needs to be clear).

Infinite non-cyclic decimal does not count as a fraction (reason:

Infinite non-cyclic decimal is not a fraction, it is an irrational number).

The decimal of the test score set should also be written.

Infinite does not loop decimals, do not need to write.

How many times is the party calculated by the computer, how to play?

Click on the calculator above to view and then select the scientific one.

And then it's going to expand a little bit, and there's an x y in the left letter, see.

For example, to the power of 3, press 3 on the right, then x y on the left, then 5 on the right, and then the dot equals and it's OK.

Magic square: First, nine numbers are given 123456789. Talk about the number in the middle and put it in the middle box.

That is, 5 put in the middle. And make sure that the sum of each row or column is three times the number in between, i.e., 15. Then divide the remaining 8 numbers into 4 pairs.

Press the smaller number from smallest to largest. Arrangement i.e. 1,9。。

Place the second and fourth pairs diagonally. That is, the left bottom of 5 is filled with 2,8. Fill in 4,6 on the lower right.

The remaining four are calculated by subtracting the other two numbers from the sum number 15.

is this your mother?With what.

Yes, she is

Negative: No, she isn't.

It should be said that rational numbers contain some decimals.

Do you know the definition of rational numbers?

A number that can be expressed as m n (the simplest fraction form, m and n are integers, and their greatest common divisor is 1) is a rational number.

From this it is clear that it may be a decimal. For example, 2 5-

Integers can always be expressed in the form m 1, so they are rational numbers but decimals are not, such as the square root of 2, which cannot be expressed in the form m n. But it's also a decimal.

A is 3 2 times that of b so a

3 2 bc is 30 ° larger than the two corners of the Hui orange, so. cab

Other. The sum of the inner angles of the triangle is 180°

So there are friends in the group. ab

c. According to the above conditions. Solution. abc

Let a=x°

Then the reputation of the world is returned to guess b=(3 2)x°, c= a+ b+30°=[5 2)x+30]°

And because the sum of the inner angles of the triangle is 180°

So a+ b+ c=180°

Therefore, since the celebration of the paragraph, it has been counted

1 sphere, 2 obtuse triangles, regular pentagons, regular hexagons 3 If the number of edges on the bottom surface of the prism is n, then the vertices of this prism are n, there are n on the sides, there are (n + 2) on the face, there are 3n on the edges, n on the side 4 The cube passes through a vertex (3

Striped edges, passing through a vertex there (3 faces.

（a+b）^2=a²＋b²+2ab

So a b = 25 - (-12) = 37

a-b)^2=a²＋b²-2ab

So a b = 25 + (-12) = 13

learn is a verb, and here well modifies the verb, not english

If it's to modify English, then it translates to English that I have to learn well, which is very inappropriate, and good should be placed in front of English.

enough must be placed after an adjective or adverb.

The whole sentence means that I have to learn English well because it is very important to get a good job in the future.

Mathematics (a+b) 2-2ab=a2 b2=37(a-b)2+2ab=a2 b2=13

In English, it's the difference between enough and different adjectives, and according to the teacher, it's some fixed usage.

I can't say very clearly, you can see how the brothers downstairs explain it to you, it's really not good, I suggest you buy a book to read this grammar knowledge, the best thing is to ask the teacher directly, of course.

(1)a2＋b2=a2+2ab+b2-2ab=(a+b)2-2ab

Substitute a b 5, ab -6.

That is, 52 + 12 = 37

2) In the same way, a2 b2 = a2-2ab + b2 + 2ab = (a-b) 2 + 2 ab

i.e. 52-12=13

It seems to be embellished by the learn....

(a+b)2=a2+2ab+b2 52=a2+2 (-6)+b2 a2+b2=25+12=37

a-b)2=a2-2ab+b2 52=a2-2 (-6)+b2 a2+b2=25-12=13

Adverbs modify verbs, adjectives, and other adverbs, etc., to illustrate concepts such as time, place, degree, and manner. Example; run fast ,very good where fast with good are adverbs.

b Because adjective + enough enough + noun, just remember this, and the adverb well modifies learn

A 2+B 2=(a+b) 2-2ab=25-(-12)=37a 2+b 2=(a-b) 2+2ab=25+(-12)=13 According to the usage of enough, we can be sure that the answer is b or c, here well is an adverb, good is an adjective, and well modifies learn, we have to learn English well enough, because it is important for us to get a good job in the future.

Because the space is filled in with the modifier learn english, modifier verb, it should be an adverb.

3.(32+x)=2[18+(28-x)]4. 60/4=15 15*3=45。Bu Zhongpei long pei buried for 45, wide for the type of only 15 looks.

-a²-b²+ab²

1-a²）-b²-ab²）

1+a)*(1-a)-b²*(1-a)=(1-a)*(1+a-b²)

When a=1/99 and b=1, substitute the above formula.

Original formula = (1-1 99)*(1+1 99-1)2, x=-2).

x to the third power + 4x -4x + k = 0

2) to the third power of +4*(-2) -4*(-2)+k=0-8+16-8+k=0

k = -16x to the third power + 4x -4x-16 factorization.

Original = x*(x -4) + (4x -16) = x*(x -4) + 4(x -4).

x²-4)(x+4)

x+2)(x-2)(x+4)

3. Original formula = 1-b -a +a b +4ab=[2ab+(ab) +1]-(a +b -2ab)=(ab+1) -a+b).

ab+1+a+b)(ab+1-a-b)

1.Original formula = (1+a)(1-a)-(1-a)b = (1-a)(1+a-b).

Evaluate = a(1-a).

1/99x98/99

2.Substituting x=-2 into the original formula, we get:

8+16+8+k=0

k = -16 factor: x 3+4x -4x-16=x 3-4x+4x -16

x(x²-4)+4(x²-4)

x+4)(x²-4)

x+4)(x+2) (x-2)