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Hebei education first edition seventh grade next semester mathematics final exam questions and reference answers. Choose carefully and make a final decision (2 points for each small question, 30 points for * * *).
1. Among the following equations, the one that belongs to binary linear equation is ().
a . 3x-4 = 7-x b . 2x+5y = 10 c . xy- 1 = 0d . x+y = 3z+7
Answer B.
From 1, we can get the formula () 322x? 22x 12x2x? C.y2 D.y? 2? Y? Baguio? 33333
Answer c
? x? m? 63. Through the equation? It can be concluded that the relationship between x and y is ()
? y? 3? m
A.x+y=9 B.x+y=3
C.x+y=-3 D.x+y=-9
Answer a.
4. For example, a∑b is known, 1=40? And then what? 2=( )
A. 140? B. 120? C. 40? D. 50?
Answer a.
5. for example, AB∨CD, AD split equally? BAC, and C=80? And then what? The degree of d is () A. 50? B. 60? C. 70? D. 100?
Answer a.
6. Of the following four shapes,? 1=? Must be true. Yes ()
Answer B.
7. For example, in Rt△ABC, ACB=90? , DE crosses point c, DE//AB, if? So ACD=500? The degree of B is ()
.50 caliber? B.40? C.30? D.25?
8. For example, the decorator nailed slats to the wall. What if? 2= 1 10? , so that batten b is parallel to a, then? The number of times 1 is equal to ()
.55 caliber? B.70? C.90? D. 1 10?
Answer B.
9. The numbers below each group represent the lengths of the three sticks. After connecting them end to end, the group that can be put into a triangle is ().
A. 1,2,6 B. 2,2,4 C
Answer D.
10. In the following operations, () must be correct.
A.m5? m2? m3 B.m 10? m2? m5 C.m? m2? m3 D.(2m)5? 2m5
Answer C.
1 1. known a? b? 1, then the algebraic expression 2a? 2b? The value of 3 is ()
A.- 1 B. 1 C.-5 D.5
Answer a.
12. If the reciprocal of a is-1, then a20 13 is equal to ().
A. 1 B.﹣ 1
So choose B.
13. Factorization factor 2x2? The final result of 4x+2 is ()
A.2x(x? 2) B.2(x2? 2x + 1) C.2(x? 1)2 D.(2x? 2)2
Answer c
14. If a>b and the following inequalities are deformed incorrectly, it is (). ..
Alcoholics Association. 1 & gt; b? 1 B . >C.3a? 4 & gt3b? 4 D.4? 3a & gt4? 3b
Answer: d
15. the equation mx about x? 1? If the solution of 2x is a positive number, the range of m is ()
Morning? Two o'clock? 2
C.m & gt2d . m & lt; 2
Answer c
2. Make the finishing point with clever thinking (2 points for each small question, *** 10)
16. The positive integer solution of binary linear equation x+y=5 has _ _ _ _ _.
Analysis: ∵x+y=5, Y=5-x, and ∵x and y are positive integers.
? X is a positive integer less than 5. When x= 1, y = 4;; When x=2, y = 3;;
When x=3 and y=2; When x=4, y= 1.
Answer B.
17. For example, line A and line B are cut by line C, if A∑B,? 1=40? ,? 2=70? And then what?
3= degrees.
The answer is 1 10.
18.△ABC, what are the three internal angles? A: B, is it? C are you satisfied? B﹣? A=? C﹣? What about B? B= degrees.
Answer 60
19. given real numbers a and b satisfy a+b=2, A-B = 5, and the value of (A+B) 3 (A-B) 3 is. So the answer is: 1000.
20. If m2-N2 = 6 and m-n = 2, then m+n=.
Solution: m2-N2 = (m+n) (m-n) = (m+n)? 2=6,
So m+n=3.
So the answer is: 3.
Three. Pass the test, victory is in sight (60 points in this question * * *)
? x? y? z? 5? x? 2y? 4? 2 1. Solve the equation (1)? (2)? x? y? 5z? 1 ? 2x? y? 3? 0? 2x? 3y? z? 14?
? x? 5? x? 2? Solution: (1)? (2)? y 1? y 1? z? 1?
22.( 1) decomposition factor: a3b-2a2b2+ab3. (2) Simplification: a( 1? a)? (a? 1)2? 1 solution: (1)a3b-2a2b2+ab3
=ab(a2-2ab+b2)
=ab(a-b)2。
(2) The original formula =a? a2? a2? 2a? 1? 1? 3a
? x? 3(x? 2)? 4? 23. Solve the inequality group? 1? 2x, and the solution set is represented by the number axis. x? 13
Answer: from 1 ①: X? 1,
Obtained from 2; x & lt4,
? The solution set of inequality is: 1? x & lt4。 On the number axis, the solution set is:
1 1? . abdominal muscle
(1) Please judge whether this proposition holds. If it is true, please prove it. If it is a false proposition, please give a counterexample; 24. Proposition: If a>b, then
(2) Please modify the proposition appropriately to make it a true proposition.
1 1 Solution: (1) Pseudo-proposition. For example, a= 1 and b=-2 conform to a>b, but are not satisfied? . abdominal muscle
1 1(2) is revised as: If a>b>0, then what? . abdominal muscle
25. Like what? B=55? ,? EAC= 1 10? , AD split equally? Are EAC, AD and BC parallel? Why? Fill in the blanks or fill in the reasons in brackets according to the following solving process.
Solution: ∫AD split? EAC,? EAC= 1 10? (known)
EAD= 1
2? EAC = _ _ _ _ _ _ _ _ _ _ _ _?
∵? B=55? (known)
B=? _________
? AD ∨ BC. ( )
Solution: ∫AD split? EAC,? EAC= 1 10? ,
EAD= 1
2? EAC=55? ,
∵? B=55? ,
B=? EAD,
? AD∨BC (same angle, two straight lines are parallel),
So the answer is: 55, EAD, (same angle, two straight lines parallel).
26. For example, AB∑CD and straight line EF intersect AB respectively, and CD is divided equally at E, F and EG? Before handing in CD point g? 1? 50, beg? 2 degrees.
Solution: Because AB∑CD, so? 1BEF? 180, (complementary angle of two parallel lines with internal angles)
So what? BEF? 130.
Because EG split it equally again? BEF, so? Figberg? 1
2? BEF? 65.
And because of ab Σ CD,
So what? 2BEG? 65. (Two straight lines are parallel and the internal dislocation angles are equal)
27. For example, it is known that points A, D and B are on the same straight line. 1=? 2,? 3=? E. verification: DE∑BC.
Proof: ∫ 1 =? 2,? AOE=? COD (equal to the vertex angle),
? At △AOE and △COD,? CDO=? E (triangle interior angle sum theorem);
∵? 3=? e,
CDO=? 3,
? DE∨BC (internal dislocation angles are equal and two straight lines are parallel).
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