1, if xa-b-2-2ya+b=3 is a binary linear equation, then a = _ _ _ _ _ _
2. Given the equation 3x+5y-3=0, if Y is expressed by an algebraic expression containing X, then Y = _ _ _ _ _ _ _
3. If +(2x-y)2=0, then x2-y = _ _ _ _ _ _ _
4. Equation 5x+7y=2 1 has _ _ _ _ _ group solutions.
5. There are X people in Team A and Y people in Team B. If 10 people are transferred from Team A to Team B, the number of Team A is half of that of Team B, and the equation can be _ _ _ _ _ _ _ _ _ _ _.
6. If it is the solution of the equation, the value of (m+n)2008 is _ _ _ _ _ _ _.
7. The nonnegative integer solution of the binary linear equation x+3y=7 is _ _ _ _ _ _ _ _ _
8, using _ _ _ _ _ _ _ method to solve the equation is relatively simple.
9. If 4a-3b=0, then _ _ _ _ _ _ _
Second, please use your discernment to think patiently and then make the right choice (3 points for each small question, *** 15 points).
10, in the following equations, belongs to the binary linear equations is ().
A, B, C, D,
The sum of 1 1 and -9x7-my 1+n is known as a monomial, so the values of m and n are () respectively.
a、m=- 1，n=-7 B、m=3，n= 1
c、m=，n= D、m=，n=-2
12, the basic idea of solving binary linear equations is ()
A, substitution method b, addition and subtraction
C, elimination, is to change the binary into a binary D, and find the value of another unknown from the value of one unknown.
13 is a solution of the equation ax-3y=2, then a is ().
a、8； B, yes; c 、-； d 、-
14, given that x and y satisfy the equation, then the value of x+y is ().
a、3 B、5 C、7 D、9
Third, please show your intelligence in logical reasoning and calculation (***8 points).
15, (20 points) Solve the following equation
( 1) (2)
16, (8 points) when y=kx+b and x= 1, y = 2；; When x=- 1, y = 4；; When x=2, what is the value of y?
17, (8 points) If the sum of the x and y values of the equation is 2, find the value of k. ..
18, (10) Find the solution of equation 2x+y=5 according to the following conditions.
(1) The value of x is equal to the value of y;
(2) The value of x and the value of y are reciprocal;
(3) the value of y is three times that of x.
19, (8 points) If the adjacent complementary angle of an angle is equal to 3 times of this angle, find this angle.
20.(8 points) The sum of three digits, one digit and the hundredth digit is equal to the number on the tenth digit. Seven times the number in the hundredth place is 2, and the sum of the numbers in the tenth place is 14. Find this three-digit number
2 1, (16) There are 23 middle school students in a mountainous area, and primary school students need to donate money because of poverty. It takes A yuan to finance the study expenses of a middle school student and B yuan to finance the study expenses of a primary school student. Students from a school actively donated money. The amount of donations from junior high school students of all grades and the number of poor middle school students and primary school students who use it to support donations are shown in the following table:
Donation amount (yuan) Number of poor middle school students (name) Number of poor primary school students (name)
The first level is 4000 2 4.
The second grade is 4200 3 3.
Grade 7400, grade three
(1) Find the values of a and b;
(2) The donation of third-grade students has solved the study expenses of other poor primary and secondary school students. How many poor primary and middle school students can the third grade students donate?
8. Party A and Party B drive at a constant speed on the circular road and meet every two minutes; Walking in the same direction, we meet every 6 minutes. It is known that A runs faster than B. How many laps do A and B run per minute?
9. There are three rooms and two rooms in the hotel. Three rooms in 30 yuan every day, two rooms in 40 yuan every day. A tour group of 60 people checked into the hotel and rented several rooms, each of which was just full. One day * * spent 2 100 yuan on accommodation. How many rooms are rented for each of the two rooms?
10. A classmate found that the unit price of his favorite walkman is the same in two supermarkets, A and B, and the unit price of walkman and schoolbag is the same. The sum of the unit price of the walkman and the schoolbag is 452 yuan, and the unit price of the walkman is four times less than that of the schoolbag. 8 yuan.
(1) What is the unit price of the walkman and schoolbag that students like?
(2) One day, the students went out to the streets, just in time for the business promotion. Supermarket A sells all goods at a 20% discount, and supermarket B bought 100 yuan and returned the shopping voucher to 30 yuan (if it is less than 100 yuan, the shopping voucher is universal), but he only brought 400 yuan money. If he only bought these two things in one supermarket, can you explain which one he would choose to buy? If both companies can choose, which one is more economical to buy?
1 1. The existing school building is 20,000 square meters. It is planned to demolish some old school buildings and build new ones, with an area of 2,000 square meters more than the demolished area. If the total area of the completed school buildings is 40% larger than that of the existing ones, how many old school buildings will be demolished? How many new school buildings have been built?
12. A processing factory has 60 workers, producing a supporting product, one bolt and two nuts. Everyone produces 14 bolts or 20 nuts on average every day. How many people do you need to produce bolts and nuts to make the produced bolts and nuts match just right?
13. A mango planting base in the old revolutionary base area had a balance of 5 million last year, and it is estimated that it will have a balance of 9.8 million this year. Moreover, this year's income is higher than last year's 15%, and the expenditure is lower than last year's 10%. What is the revenue and expenditure this year?
The "Spring Cup" math contest has 14 and 10 questions. Xiao Ming scored 77 points and did every question, but he felt that the score was a little different from his self-evaluation. It is known that 10 points for each question, and 10 points will not be deducted. If part of it is done correctly, he will get 3 points.
15, there is a two-digit number, the number in the tenth place is less than the number in the second place 1, and the sum of the number in the tenth place and the number in the second place is 1/5 of this two-digit number. Find this two-digit number?
Reference answer:
I. 1。 2.2; 3.3; 4. Countless; 5.； 6. 1; 7.
8. Add and subtract; 9.
ii . 10 . c； 1 1.b； 12.c； 13.b； 14.B。
Three. 15.
16. When x=2, the value of y is 1.
17.
18.
19.；
20.275;
2 1.( 1)
(2) The number of poor primary and secondary school students who can be donated by grade three students is 4 and 7 respectively.
9. triple room 10 room, double room 15 room.
10, (2) It takes cash to buy a walkman and a schoolbag at Supermarket A:
452×80%=36 1.6 yuan.
Because 36 1.6