Multiplication of polynomials 100 points Good add 10 points

The above answers are basically correct, but the sixth question is wrong, because there should be a sidewalk on both sides of the length and width of the tennis court, so the length and width of the tennis court should be (80-2x) and (60-2x).

then the area is (80-2x)· (60-2x) = 4x 2-280x+4800 (Note: x 2 represents the square of x).

If you can't understand it, just take a look.

In addition, in the seventh question, let their difference be x, and if this x is known, then the equation can be listed.

n+2)(n+3)-n(n+1)=x

After simplification, it becomes 4n+6=x, because x is known, you can find the value of n, know the value of n, and soon get the other three numbers!

One. Fill in the blank 1)(x+1)·(x+2)=x 2+3x+22)(x-1)· (x-2)=x2-3x+2two. (x+2)·(x-2)=x^2-4

3x-1)· (2x+1)=6x 2+x-1x-3y)· (x+7y)=x 2+4xy-21y 22x+5y)· (3x-2y) = 6x 2 + 11xy-10y 2 three. Simplification -4x+1)· (2x+3)-(8x)· (x+1)-8x 2-10x+3+8x 2+8x

3-2x four. Simplify first, then evaluate.

2（x-8)· (x+5)-(2x-1)· (x+2), where x=-72x 2-6x-80-(2x 2+3x-2)2x 2-6x-80-2x 2-3x+2

9x-78 V. （x+1)· (x+a) = x to the second power + 4x+3, the value of a is (b) a:4 b:3 c:2 d:-3

x+1)·(x+a)x

x^2+x+ax+a

x^2+(a+1)x+a

a=3 six.

80-x)(60-x)

x^2-140x+4800

7. n+2)(n+3)-n(n+1).

n^2+5n+6-n^2-n

4n+6

Multiply each term in a polynomial by each term of another polynomial, and finally merge terms of the same kind.

The multiplication operation of a polynomial is actually taking one of the polynomials as a whole and converting "many" into (one times many).

You take my words first, and then I'll write you the answer.

1.Natural beauty Natural beauty Healthy beauty Modified beauty.

2 can·· Leather shoes Cloth shoes and travel shoes are not possible.

3 The index finger ——— want to get married, which means that you are not married.

4.I don't really understand that it should be to keep your head up and your chest high.

5 Outer Appearance Inner qualities.

6. b7..a c f

8 b c d

9 a10. a b

11.It refers to the clothing of the whole body, which should be kept within the three colors.

12.That is, it is to do not offend anyone.

13 Dress should be relevant to the time at that time. The occasion and the place are in harmony.

14 The "Three A's" are the capital on which business etiquette stands.

15. Fully display the achievements of the Chinese in building socialist spiritual civilization and the spirit of self-improvement and self-confidence under the leadership of the Communist Party in front of foreigners; The friendship and sincerity between the Chinese and the people of the world.

16 Politeness refers to a person's moral character, and etiquette refers to the outward manifestation of a person's character. A polite person relies on etiquette to show respect for others. For example, when a polite student talks to a teacher, he will show respect for the teacher through his standing or sitting posture and the humility of the conversation.

Etiquette refers to the whole of multiple etiquette in a complex event. For example, on Teacher's Day, in order to express their respect and gratitude to their teachers, students often give speeches, lay flowers, perform condolence performances, and present greeting cards at the celebration ......A series of etiquette constitutes etiquette to the teacher.

17 We emphasize that the image of the individual is the unity of the inner quality and the external style. Although some people have increased their wealth, they have the conditions to dress themselves, wear famous brands, live in high-end hotels, and have beauty salons; If his quality is not improved, his words, deeds, and demeanor will still remain at a low level of quality, resulting in a distortion of inconsistency inside and outside the image. The nouveau riche are often referred to as typical representatives.

Although they are rich and can be dressed up in a rich and glamorous appearance, their temperament and cultivation are still vulgar.

18. "Smile service" is a professional requirement, and you should learn to smile; If you are satisfied with your profession, have professionalism, and have a sincere smile from the heart, it is good; However, if you can't do this, you should also cultivate a smile that makes customers feel friendly and avoid blunt "disguises".

19 Self-esteem refers to the struggle of personality and national character in the event of a deliberate insult from the other side; Tolerance refers to the fact that the other party has unintentionally made a faux pas or a faux pas due to differences in customs, which should be tolerated, and there is no contradiction between the two.

1 kilogram kilogram 2 kilogram kilogram kilogram are all errors of the meaning of the error as long as the error is counted

2 Walk 100 meters north and reverse up, north, down, south, left, west, right, east, ......

3 is also the margin of error, qualified, all within the error range, the upper limit of the error is 630ml, the lower limit is 570ml, and it is obviously within the range.

4 40+ add and divide by 2 to take the average and then consider the difference between the individual numbers and the average The average is 40

5 Same as above The average is.

Positive and negative numbers can represent the value and can also represent the range of values You are the basis of the range error calculation, just like the pH value of pure water, there will be 7 + words, because many manufacturers of raw materials, including the difference in technology, will make the nature of the product change slightly, so for the benefit of manufacturers and consumers, the error range of the product must be clarified

I hope you are satisfied with my answer

1. 2+, 2+0, 2+,2.You imagine walking backwards 100m facing southIt's 100m3 to the north

The error of the indicated content can be within plus or minus 30ml. That is, it is normally allowed within [600-30ml, 600+30ml]. Fully qualified.

4.(This is the median value.) , 40+(2) (follow the same as above or subtract it.)

Kilogram Kilogram 2 kilogram kilogram kilogram; Error relationship 2, that is, go 100 meters to the north; According to the question, if you go -100m to the south, you will go negative, and if you want to change -100 to +100, you will have to reverse the direction, so you will go 100 meters to the north.

30 = 630, 600-30 = 570, 570 x 630 are all passing, and the above 5 bottles are qualified; Because the conditions are 600+30 and 600-30, no greater than the sign should be used.

4. (1) > use a greater than sign.