1. Among the following equations, () is a binary linear equation.
a . 3x-y2 = 0 b .+= 1 c .-y = 6d . 4xy = 3
2. If 2x-7y=8, then it is () to correctly represent X with an algebraic expression containing y..
A.y= B.y= C.x= D.x=
3. The solution of the equation is ()
A.B. C. D。
4. If 4x-3y=0, the value of is ().
A.31B.-C.D. Not sure.
5. It is known that x=2, y=- 1 is a solution of equation 2ax-y=3, so the value of a is ().
1
6. In the following groups, the solutions of equation 2x-y=3 and equation 3x+4y= 10 are ().
A.B. C. D。
7. If the sum of xa+ 1y-2b and -x2-by2 is a monomial, the values of a and b are () respectively.
A.a=2，b=- 1 B.a=2，b= 1 C.a=-2，b= 1 D.a=-2，b=- 1
8. The number of nonnegative integer solutions of equation 3x+2y=5 is ().
1。
9. If the solution of binary linear equations is the solution of binary linear equations 2x-3y+ 12=0, then the value of a is ().
A.b .-c . d-
10. If (x+y-5)2 and │3y-2x+ 10│ are antonyms, then the values of x and y are ().
A.x=3，y=2 B.x=2，y=3 C.x=0，y=5 D.x=5，y=0
165438+
A. neither profit nor loss; B. it can be profitable1%; C. loss of 2%; D. it will lose 1%.
12. As shown in the figure, the endpoint o of the light oc is on the straight line AB, and the degree of ∠AOC is more than that of ∠BOC 10. Let the degrees of ∠AOC and ∠BOC be x and y respectively, then the following correct equation is ().
A.B.
C.D.
Fill in the blanks (this big question is ***8 small questions, each with 3 points and ***24 points. Fill in the answers on the lines in the questions)
13. It is known that xm- 1+2yn+ 1=0 is a binary linear equation, then m=_______, and n = _ _ _ _ _.
14. in the equation y=kx+b, when x=0, y =-1; When x= 1 and y=2, then k = _ _ _ _ _, and b = _ _ _ _ _.
15. It is known that m-3n=2m+n- 15= 1, then m = _ _ _ _ _ _ _, and n = _ _ _ _ _.
16. As shown in the figure, the rectangular ABCD with a circumference of 68cm is divided into seven identical rectangles, and the area of the rectangular ABCD is _ _ _ _ _ _ _ _.
17. A large planter plans to cultivate 30 mu of land with 10 labor force. These lands can be used to grow vegetables and rice. The labor force required for planting these crops and the estimated output value are as follows:
Labor force required per mu (unit)
Estimated output value per mu (yuan)
vegetables
3000
paddy field
700
In order to grow crops on all the land, all the laborers have jobs, and the labor force for growing vegetables should be _ _ _ _ _ _ _ _, and the estimated output value at this time is _ _ _ _ _ _ _ _.
18. The solution of the equation is _ _ _ _ _ _.
19. The speed of the ship sailing downstream is m km/h, and the speed of sailing upstream is n km/h, so the speed of the current is _ _ _ _ _ _ _ _.
20. If the sum of a two-digit number and a ten-digit number is 5, then the number of such two-digit numbers is _ _ _ _ _.
Third, solve the problem (this big question ***4 small questions, ***40 points, the answer should be written to explain the process or calculus steps)
2 1. Solve the following equation. (4 points for each small question, *** 16 points)
( 1) (2)
(3) (4)
22.(6 points) m is a positive integer, and it is known that binary linear equations have integer solutions, so find m.
23.(8 points) As shown in the figure:
24.( 10) During the "May Day" period, a shopping mall engaged in preferential sales promotion and decided to let customers draw lots to decide the discount. A customer buys two kinds of goods, A and B, and gets a 386 yuan discount (30% off the selling price) and a 10% discount (10% off the selling price) respectively. The sum of the original prices of these two commodities is 500 yuan.
Answer:
1.C 2。 C 3。 A
4. Type B dial: ∫4x-3y = 0, ∴ 4x = 3y.
= =, so choose B.
5.B-Cue: From the concept of the solution of the equation, we know that 2A× 2-(- 1) = 3. ∴ A =, so we choose B.
6.C
7. A nudge: xa+ 1y-2b and -x2-by2 are similar projects according to the meaning of the question.
I got the solution, so I chose A.
8. nudge: y = from 3x+2y=5.
The solution is 0≤x≤ x ≤。
X can get 0, 1.
When x=0, y= is irrelevant and should be omitted;
When x= 1, y = = 1.
The number of non-negative integer solutions of equation 3x+2y=5 is 1, so a is chosen.
9.b nudge: take a as a known number and solve the equation.
To understand the equation, we must substitute 2x-3y+ 12=0.
2×6a-3×(-3a)+ 12=0, and the solution is a =-.
10.d nudge: we know from the concept of reciprocal.
(x+y-5)2+│3y-2x+ 10│=0。
∴ Choose D as the answer.
1 1.d dial: after the price adjustment, the purchase price of two air conditioners sold at profit and loss is X yuan and Y yuan respectively.
Then (1+10%) X = (1-10%) Y. Finishing, X = Y.
∴=- 1%.
That is, the mall will lose 1%, so choose D.
12.b 13.2； 0 14.3; - 1
15.7; 2-point dialing: it is known that m-3n=2m+n- 15= 1,
Available solutions
16.280cm2 nudge: Pay attention to the figure, knowing that the length of two small rectangles is equal to the width of five small rectangles.
Let a small rectangle be xcm in length and ycm in width.
solve
The area of rectangular ABCD is (10+4) × 2×10 = 280 (cm2).
17.5; 44,000 points: Assuming that the labor force for planting vegetables is X, the estimated output value is Y yuan.
From the meaning of the question, get
solve
18.
Dial:
①+② 2│x│=8，∴│x│=4，∴ x = 4。
①-② 2y=2，∴ y = 1。
∴
19.20.5 pieces/km/hour
2 1.( 1) (2) (3) (4)
22. Solution: Solve the equation.
①+② Get (m+3)x= 10, ∴x=
Substitute x= into ② to get y =.
∵m is a positive integer, and the solution of the equations is an integer.
∴m is a positive integer, and x= and y= are both integers.
∴m=2,m2=4.
Hugging: Because M is necessary, it has nothing to do with X and Y. 。
So let m be a known number, and let m represent x and y.
23. Solution: Setting up a notebook costs X yuan and a pen costs Y yuan, depending on the meaning of the problem.
To solve this equation, you must
Answer: 1 Notebook needs 2 yuan, 1 Pen needs 4 yuan.
24. solution: suppose that the original sales prices of a and b commodities are x yuan and y yuan respectively, depending on the meaning of the question.
solve
A: The original selling prices of A and B were 320 yuan and 180 yuan respectively.