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Answers to ABC group review questions in eighth grade mathematics of Shanghai Science and Technology Publishing House
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Fill in the blanks: (2 points for each small question, ***20 points)

(1) The equation 2x-3y+4 = 0 is known. If x is represented by an algebraic expression containing y, it should be written as _ _ _ _ _ _ _ _.

(2) given that x=5 and y=7 satisfy KX-2Y = 1, then K = _ _ _ _ _ _ _ _

③ Inequality 2x-4

(4) 0.0987 is _ _ _ _ _ by scientific notation.

(5)__________。

(6) As shown in the figure, ∠1= _ _ _ _ _ _.

(7) As shown in the figure, the conformal angle of ∠3 is _ _ _ _ _ _.

(8) The northeast direction is _ _ _ _ _ _ _ due north by east.

(9) Rewrite "There is only one intersection point between two straight lines" as "If".

(10) It is known that all three points A, B and C are on the straight line L, and AB = 5cm and BC = 6cm, then the length of AC is _ _ _ _ _ _ _ _.

Second, multiple-choice questions: (3 points for each small question, ***24 points)

Of the four options given in each question, one and only one is correct. Please put the alphabetic code before the correct option in brackets.

The solution set of (1) unary linear inequality is ().

(A)x & gt; -8 (B)x<-8(C)x & gt; -2(D)x & lt; -2

(2) The following shows that the correct process of finding the solution set of inequality group is () on the number axis.

(3) The following calculation error is ().

① ②

③ ④

⑤ ⑥

Six (b) five (c) four (d) three

(4) The following multiplication formula is correct ().

(A)4 (B)3 (C)2 (D) 1。

(5) The correct one in the following drawing statement is ().

(a) extend the straight line PQ (B) as the midpoint o of the ray MN.

(c) The bisector MN (D) of the straight line AB is the bisector OC of ∠AOB.

(6) Among the following propositions, the straight proposition is ().

(a) The two acute angles must be complementary.

(b) Two complementary angles are adjacent complementary angles.

(c) The complementary angles of equal angles are equal.

(d) If AM = MB, point M is the midpoint of line segment AB.

(7) Angles smaller than right angles are divided into three categories according to size ().

(1) acute angle, right angle and obtuse angle (2) internal dislocation angle and internal angle on the same side.

(c) Round corners, right angles and right angles (d) Top angles, complementary angles and complementary angles.

(8) In plane geometry, the false proposition in the following propositions is ().

(a) Two lines parallel to the same line are parallel.

(b) There is only one straight line between two points.

(c) There is one and only one straight line parallel to the known straight line at one point.

(d) There is one and only one straight line perpendicular to the known straight line.

3. Calculate the following questions: (small questions (1)~(6)2 points, small questions (7) and (8)3 points, *** 18 points).

( 1)__________

(2)__________

(3)__________

(4)5x(0.2x-0.4 years) = _ _ _ _ _ _ _ _

(5)__________

(6)__________

(7)

Solution:

(8)

Solution:

Fourth, solve the following linear equations and linear inequalities of one variable: (5 points for each small question, *** 10).

( 1)

Solution:

(2)

Solution:

5. Drawing questions: (Draw with a scale, triangle, protractor or ruler, not writing, only requiring the picture to be accurate. ) (65438+ 0 point for each small question, ***3 points).

(1) The point where the parallel line M passes through A is BC;

(2) Point A is the vertical line of BC, and the vertical foot is point D;

(3) The length of the line segment _ _ _ _ _ _ is the distance from point A to BC.

6. Fill in the blanks in the following reasoning process, and fill in the blanks with the basis of this reasoning step (65438+ 0 points per space, ***7 points).

As shown in the figure, AD//BC (known),

∴∠DAC=__________().

∫∠BAD =∠DCB (known),

∴∠BAD-∠DAC=∠DCB-__________,

That is to say, ∞ _ _ _ _ _ = ∞ _ _ _ _ _ _.

∴AB//__________().

Seven, solve the problem of equations: (5 points for each small question, *** 10)

(1) I bought 10 stamps, 20 stamps and 50 stamps with 3 yuan 50 * *18 stamps. The total face value of 10 stamp is the same as that of 20 stamps. How many stamps did I buy each of these three stamps?

Solution:

(2) The complementary angle of ∠ABC is greater than that of ∠MNP, and the complementary angle of ∠ ABC is greater than that of ∠MNP. Find the degree of ∠ ABC and ∠MNP

Solution:

Eight. Proof question: (5 points for this question)

Known: as shown in figure ∠ BDE+∠ ABC =, BE//FG.

Proof: ∠ Deb = ∠ GFC.

Prove:

Nine, it is known that the solution of the equation about x and y is the same as the solution of the equation, and the values of m and n are found. (3 points for this question)

Solution:

Reference answers and bisection criteria

Fill in the blanks

(2 points for each small question, ***20 points)

( 1) (2)3

(3)x & lt; 2 (4)

⑸4xy⑹ 100

(7)& lt; 7 (8)45

(9) If two straight lines intersect, there is only one intersection point, (1 0) 1cm or1cm (if only one of them is written,1minute can be given).

Second, multiple-choice questions (3 points for each small question, ***24 points)

BBAD·DCAC

Three. Calculate the following questions: (2 points for minor questions (1) ~ (6), 3 points for minor questions (7)(8), *** 18.

( 1) (2) (3) (4)

(5) (6)

(7) (If the result is wrong and the process is correct, you can give 1 minute)

(8) Original formula .......................................... 1 min.

Three points

Four, solve the following linear equations and linear inequalities (5 points for each small question, *** 10).

(1) Answer:

Correctly exclude 2 points.

Correctly solve the value of an unknown ............................................................................................... 4 points.

Complete the solution of the equation 5 points.

(2) answer:.

2 points for correctly solving the solution set of each inequality in the inequality group.

Get the correct answer and get 1 point.

The solution set of the first inequality is written as x < 8, or finally get -3, otherwise it is correct, get 4 points.

Fifth, drawing questions. (65438+ 0 point for each small question, ***3 points)

Six, (per grid 1 minute, ***7 points)

∠BCA, (two straight lines are parallel with equal internal angles)

∠BCA∠BAC∠DCA,

DC, (offset angle is equal, two straight lines are parallel)

Seven. Solving application problems with equations: (5 points for each small question, *** 10)

(1) Solution: Suppose 10 bought x stamps, y stamps for 20 stamps and z stamps for 50 stamps. ................. 1 point

So ... three points.

The solution is 4 o'clock.

A: 10 bought 10 stamps, 5 stamps for 20 and 3 stamps for 50. Five points.

(2) Solution: Let ∠ABC be and ∠MNP be. ................................ 1 min.

So ... three points.

The solution is 4 o'clock.

A: ABC is, MNP is. Five points.

Eight, proof questions. (5 points for this question)

Proof: ∫∠BDE+∠ABC =,

∴DE//BC, 2 points

∴∠DEB=∠EBF。 Three points

∵BE//FG,

∴∠EBF=∠GFC, 4 points.

∴∠DEB=∠GFC。 Five points.

9. Solution: The solution of the equations is the same as that of the equations.

The solution of ∴ is the same as that of the equation.

The fraction of solving the equation is

Substitution equation

To understand this system of equations, you must get

Replace in my =- 1

∴,。 Three points

I. Fill in the blanks (1×28=28)

1, in the following algebraic expression:13x+5Y2X2+2x+Y2304-XY253x = 06, there are _ _ _ _ monomials and _ _ _ _ polynomials.

2. The coefficient of the monomial -7a2bc is _ _ _ _ _, and the degree is _ _ _ _.

3. Polynomial 3a2b2-5ab2+a2-6 is a _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

4、3b2m? (_ _ _ _ _ _ _)= 3b4m+ 1-(x-y)5(x-y)4 = _ _ _ _ _ _ _ _(-2a2b)2 \\) = 2a

5 、(-2m+3)(_ _ _ _ _ _ _ _ _ _ _ _)= 4 m2-9(-2ab+3)2 = _ _ _ _ _ _ _ _ _ _ _ _ _

6. If ∠ 1 and ∠2 are complementary angles, then ∠ 1=72? ,∠2=_____? , if ∠3=∠ 1, the complementary angle of ∠3 is _ _ _ _? The reason is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

7. In the picture on the left, if ∠A+∠B= 180? ,∠C=65? , then ∠1= _ _ _? ,

A 2D ∠ 2 = _ _ _ _ _? .

B.C.

8. In biology class, the teacher told the students: "Microorganisms are very small, and the diameter of dendrites is only 0. 1 micron", which is equivalent to _ _ _ _ _ _ _ _ meters (1 meter = 106 micron, please use scientific notation).

9. In the group's self-editing and self-answering activities, Xiao Fang gave the group members such a question: Zu Chongzhi, an ancient mathematician in China, found that pi = 3. 14 15926 ..., the approximate value was 3. 14, and the accuracy was _ _ _ _ _ _.

Xiao Ming, Xiao Gang and Xiao Liang are playing games. Now, if one of them is helping Grandma Wang, P (Xiaoming is selected) = _ _ _ _ _, P (Xiaoming is not selected) = _ _ _ _ _.

1 1. Throw a dice at will, calculate the probability of the following events and mark them in the figure below.

(1) The number of throwing points is even (2), and the number of throwing points is less than 7.

(3), the number of throwing points is two digits (4), and the number of throwing points is a multiple of 2.

0 1/2 1

Impossible, inevitable.

Second, multiple-choice questions (2×7= 14)

1. In math class today, the teacher talked about polynomial addition and subtraction. After school, Xiao Ming came home and took out his class notes. He carefully reviewed what the teacher said in class. He suddenly found a problem: (-x2+3xy- y2)-(- x2+4xy- y2)= ah.

The space of-x2 _ _ _+y2 is stained with ink, so one of the spaces is ().

a、-7xy B、7xy C、-xy D、xy

2, the following statement, the correct is ()

A, the complementary angle of an angle must be obtuse B, and the two acute angles must be complementary angles.

C, the right angle has no complementary angle d, if ∠MON= 180? Then m, o and n are in a straight line.

3. In math class, the teacher gave the following data, () is accurate.

In 2002, the American war in Afghanistan cost $654.38 billion per month.

B, the coal reserves on the earth exceed 5 trillion tons.

C, the human brain has 1× 10 10 cells.

D, you got 92 points in this midterm.

4. The probability that the puppy walks around on the square brick as shown in the figure and finally stops on the shadow square brick is ()

A, B,

C, D,

5. If ∣ x ∣ = 1 and ∣ y ∣ = are known, then the value of (x20)3-x3y2 is equal to ().

A,-or -B, or c, d,-

6, the following conditions can't get a‖b is () C ..

a、∠2=∠6 B、∠3+∠5= 180? 1 2 a

c、∠4+∠6= 180? d、∠2=∠8 5 6 b

7. Among the following four figures, ∠ 1 and ∠2 are diagonal figures ().

a、0 B、 1 C、2 D、3

Third, the calculation problem (4×8=32)

⑴ -3(x2-xy)-x(-2y+2x) ⑵ (-x5)? x3n- 1+x3n? (-x)4

⑶(x+2)(y+3)-(x+ 1)(y-2)⑷(-2m2n)3? mn+(-7m7n 12)0-2(mn)-4? m 1 1? n8

5] (5x2y3-4x3y2+6x) ÷ 6x, where x =-2 and y = 2 [6] (3mn+1) (3mn-1)-(3mn-2) 2.

Calculate by multiplication formula:

⑺ 9992- 1 ⑻ 20032

Fourth, fill in the blanks by reasoning (1×7=7)

A known: as shown in the figure, DG⊥BC AC⊥BC, EF⊥AB, ∠ 1=∠2.

Verification: CD⊥AB

F certificate: ∵⊥ DG, BC, AC ⊥ BC (_ _ _ _ _ _ _).

∴∠DGB=∠ACB=90? (definition of vertical)

∴DG‖AC(_____________________)

∴∠2=_____(_____________________)

∠ ∠1= ∠ 2 (_ _ _ _ _ _ _ _ _) ∴1= ∠ DCA (equivalent substitution)

∴ef‖cd(______________________)∴∠aef=∠adc(____________________)

∵EF⊥AB ∴∠AEF=90? ∴∠ADC=90? Namely CD⊥AB

V. Answer questions (1 question 6 points, 2 questions 6 points, 3 questions (1) 2 points, 2 points, 3 points, a total of 19 points)

1, Xiaokang village is undergoing green space transformation. There used to be a square green space, but now each side of it has increased by 3 meters, and the area has increased by 63 square meters. What is the side length of the original green space? What is the area of the original green space?

2. Known: as shown in the figure, AB‖CD, FG‖HD, ∠B= 100? FE is the bisector of ∠CEB,

Find the degree of ∠EDH

A F pt

E

B H

G

D

3. The figure below is the statistical chart of pocket money expenditure for one week (unit: yuan).

Analyze the picture above and try to answer the following questions:

(1) On which day of the week do you spend the least pocket money? how much is it? How much did he spend on the day when he spent the most pocket money?

On which days did he spend the same amount of pocket money? What is the difference?

Can you help Mingming figure out how much pocket money he spends on average every day for a week?

Ability test paper (50 points)

(Volume II)

I. Fill in the blanks (3×6= 18)

1. There is a rectangular wooden box one meter long, two meters wide and three meters high in the room. It is known that the thickness of the board is x meters, so the volume of this wooden box is _ _ _ _ _ _ _ _ _ _ cubic meters. (Unexpanded)

2. The maximum value of Formula 4-a2-2ab-b2 is _ _ _ _ _.

3. If 2×8n× 16n=222, then n = _ _ _ _ _ _

4. Known = _ _ _ _ _ _.

5. If a little boy throws a uniform coin twice, the probability is _ _ _ _ _ _ _.

6, a as shown in the figure, ∠ABC=40? ,∠ACB=60? , BO and CO share equally ∠ABC and ∠ACB,

D E DE passes through point O and DE‖BC, then ∠ BOC = _ _ _ _ _ _ .

B.C.

Second, multiple-choice questions (3×4= 12)

1, the complementary angle of an angle is its complementary angle, then this angle is ()

60? b、45? c、30? d、90?

2. For a polynomial of degree six, the degree of any term ()

A, all less than 6 B, all equal to 6 C, all not less than 6 D, all not more than 6.

3. The correct judgment of formulas -mn and (-m)n is ().

A, these two formulas are opposite. B, these two formulas are equal.

C. when n is odd, they are reciprocal; When n is an even number, they are equal.

D, when n is even, they are reciprocal; When n is odd, they are equal.

4. It is known that the sides corresponding to two angles are parallel to each other, and the difference between these two angles is 40? , then these two angles are ()

a、 140? And 100? b、 1 10? There are still 70? c、70? What about 30 years old? d、 150? And 1 10?

Three, drawing questions (don't write, keep drawing traces) (6 points)

Use a ruler to make a straight line m parallel to the straight line n through point A (flat push can't be made).

Answer?

n

Fourth, solving problems (7×2= 14)

1. If the product of polynomial x2+ax+8 and polynomial x2-3x+b does not contain x2 and x3 terms, find the value of (a-b)3-(a3-b3).

3. As shown in the figure, it is known that AB‖CD, ∠A=36? ,∠C= 120? Find the size ∠ f-∠ e f-∠ e.

A b

E

F

C D