Can someone help me solve this problem? Z = x + y x + y-2z = 3x + 2x-y + 2y-3x = 5. What are the values of X, y and Z? Please list the equations Z = x + y x + y-2z = 3x + 2x-y + 2y-3x = 5 what are the values of X, y and Z? Please list the equation and calculation process

Can someone help me solve this problem? Z = x + y x + y-2z = 3x + 2x-y + 2y-3x = 5. What are the values of X, y and Z? Please list the equations Z = x + y x + y-2z = 3x + 2x-y + 2y-3x = 5 what are the values of X, y and Z? Please list the equation and calculation process

Let's eliminate x + y first
Z-2Z =3 Z = -3
The third form
3X+Y-3X=5
Y =5
X = -8

Try to construct an equation whose solution is x = 3, and work out an application problem according to this equation

A pen costs 7 yuan and a pencil costs 1 yuan. Xiao Ming bought some pens and 5 pencils, which cost 26 yuan. How many pens did he buy? Suppose: bought x pens. From the question meaning: 7x + 5 = 26, solution: x = 3. Answer: bought 3 pens

Observe and analyze the following equations: 1. X + x 2 / 3 = 3, 2. X + x 6 / 6 = 5, 3. X + x 12 / 7. Please use the law they contain to find the root of the equation x + x-3 / N to the second power + n = 2n + 4 (n is a positive integer)

How to calculate 2 ^ [log2 (1 / 3)] = 1 / 3,

The formula m ^ (logmn) = n is called logarithmic identity
The proof process is very simple. Let the logarithm of log with m as the base n = the logarithm of log with m as the base n (*)
If the logarithm of log with m as the base and N as a constant, the (*) expression is transformed into exponential form
The log of M is based on M, and the logarithm power of n = n

Mathematics MX square - (3m-1) + 2m-1 = 0, its root discriminant B square-4ac value is 1, find the value of M and the root of the equation

Bsquare-4ac = 1 = (3m-1) ^ 2-4 * m * (2m-1)
9m^2-6m+1-8m^2+4m-1=0
m^2-2m=0
m(m-2)=0
M = 0 or M = 2
Because the quadratic equation has the root discriminant, so m ≠ 0
So m = 2
The equation is
2x^2-5x+3=0
(2x-3)(x-1)=0
X = 3 / 2 or x = 1

In the inequality, divide the number on the right (positive or negative) of the inequality by a negative number on the left. Do you want to change the sign of the inequality
Please explain clearly and give some examples

Well, it depends on the situation
If the number on the right is positive, divide it by the negative number on the left. For example, negative 2x, negative 7 / 2
If the right is a negative number and the left is also a negative number, there is no need to change the sign. For example, the solution of negative 2 x > negative 7 is x > 7 / 2

M ā Mo group words

Rub "m" s "
Press gently with your hand to move. Also called "Mosha". Also called "Mosha"

Given the analytic expression of a straight line and the coordinates of a point, the formula for finding the symmetric point of the point with respect to the straight line?
The linear analytical formula y = - 1, 2x + B, the point coordinates (0, 1), write down the formula and solution,

The equation of the line y = KX + B passing through the point P (m, n) perpendicular to the line is y-n = - 1 / K (x-m) y = KX + B y-n = - 1 / K (x-m) intersection x = (kn-bk-m) / (k ^ 2 + 1) y = K (kn-bk-m) / (k ^ 2 + 1) + BP (m, n)

Grade six, four arithmetic problems, 100, hurry up

1. 3/7 × 49/9 - 4/3
2. 8/9 × 15/36 + 1/27
3. 12× 5/6 – 2/9 ×3
4. 8× 5/4 + 1/4
5. 6÷ 3/8 – 3/8 ÷6
6. 4/7 × 5/9 + 3/7 × 5/9
7. 5/2 -（ 3/2 + 4/5 ）
8. 7/8 + （ 1/8 + 1/9 ）
9. 9 × 5/6 + 5/6
10. 3/4 × 8/9 - 1/3
11. 7 × 5/49 + 3/14
12. 6 ×（ 1/2 + 2/3 ）
13. 8 × 4/5 + 8 × 11/5
14. 31 × 5/6 – 5/6
15. 9/7 - （ 2/7 – 10/21 ）
16. 5/9 × 18 – 14 × 2/7
17. 4/5 × 25/16 + 2/3 × 3/4
18. 14 × 8/7 – 5/6 × 12/15
19. 17/32 – 3/4 × 9/24
20. 3 × 2/9 + 1/3
21. 5/7 × 3/25 + 3/7
22. 3/14 ×× 2/3 + 1/6
23. 1/5 × 2/3 + 5/6
24. 9/22 + 1/11 ÷ 1/2
25. 5/3 × 11/5 + 4/3
26. 45 × 2/3 + 1/3 × 15
27. 7/19 + 12/19 × 5/6
28. 1/4 + 3/4 ÷ 2/3
29. 8/7 × 21/16 + 1/2
30. 101 × 1/5 – 1/5 × 21
31.50＋160÷40 （58+370）÷（64-45）
32.120-144÷18+35
33.347+45×2-4160÷52
34（58+37）÷（64-9×5）
35.95÷（64-45）
36.178-145÷5×6+42 420+580-64×21÷28
37.812-700÷（9+31×11） （136+64）×（65-345÷23）
38.85+14×（14+208÷26）
39.（284+16）×（512-8208÷18）
40.120-36×4÷18+35
Score calculation
17/32 – 3/4 × 9/24
3 × 2/9 + 1/3
5/7 × 3/25 + 3/7
3/14 ×× 2/3 + 1/6
1/5 × 2/3 + 5/6
9/22 + 1/11 ÷ 1/2
5/3 × 11/5 + 4/3
45 × 2/3 + 1/3 × 15
7/19 + 12/19 × 5/6
1/4 + 3/4 ÷ 2/3
8/7 × 21/16 + 1/2
101 × 1/5 – 1/5 × 21
3/7 × 49/9 - 4/3
8/9 × 15/36 + 1/27
12× 5/6 – 2/9 ×3
8× 5/4 + 1/4
6÷ 3/8 – 3/8 ÷6
4/7 × 5/9 + 3/7 × 5/9
5/2 -（ 3/2 + 4/5 ）
7/8 + （ 1/8 + 1/9 ）
9 × 5/6 + 5/6
3/4 × 8/9 - 1/3
7 × 5/49 + 3/14
6 ×（ 1/2 + 2/3 ）
8 × 4/5 + 8 × 11/5
31 × 5/6 – 5/6
9/7 - （ 2/7 – 10/21 ）
5/9 × 18 – 14 × 2/7
4/5 × 25/16 + 2/3 × 3/4
14 × 8/7 – 5/6 × 12/15
17/32 – 3/4 × 9/24
3 × 2/9 + 1/3
5/7 × 3/25 + 3/7
3/14 ×× 2/3 + 1/6
1/5 × 2/3 + 5/6
9/22 + 1/11 ÷ 1/2
5/3 × 11/5 + 4/3
45 × 2/3 + 1/3 × 15
7/19 + 12/19 × 5/6
1/4 + 3/4 ÷ 2/3
8/7 × 21/16 + 1/2
101 × 1/5 – 1/5 × 2
solve equations
1. If you drive 60 kilometers per hour, you will arrive half an hour earlier than planned; if you drive 45 kilometers per hour, you will be 45 minutes late. How many hours will it take to complete the whole journey?
2. A total of 210 pencils of type A and type B were bought. The price of type a pencils was 3 jiao and that of type B pencils was 4 jiao. The two pencils cost the same amount of money. How many pencils did type a buy?
3. There are 120 tons of coal in plant a and 96 tons in plant B. plant a burns 15 tons of coal every day, and plant B burns 9 tons of coal every day. How many days after that, the amount of coal left in the two plants is equal?
4. If you sell a certain kind of children's clothing, you can make a profit of 50 yuan per piece. If you sell it at a 25% discount on the sales price, the profit is 30 yuan less than the original, then what is the purchase price of this kind of children's clothing?
5. The distance between a and B is 144 km. The speed of a is 65 km / h, and that of B is 55 km / h. how long does it take for them to meet each other?
6. It takes 5 hours and 30 minutes for a plane to fly between a and B cities in the downwind and 6 hours in the upwind. If the wind speed is 24 kilometers per hour, what is the distance between the two cities?
7. A passenger train is 200 meters long and a freight train is 280 meters long. They run in opposite directions on parallel tracks. After 15 seconds from meeting to leaving at the end of the train, the speed ratio of the passenger train to the freight train is 5:3?
8. In the aircraft model competition, the first model aircraft flew 480 meters less than the second model aircraft. It is known that the speed of the first model aircraft is 1 m / s faster than that of the second model aircraft. The flight time of the two model aircraft in the air is 12 minutes and 16 minutes respectively. How much distance did the two model aircraft fly?
9. A circular runway is 400 meters long. A travels 80 meters per minute and B 120 meters per minute. Party A and Party B start from the same place at the same time. How many minutes later do they meet for the first time? If they start from the opposite direction, how many minutes later do they meet?
10. Party A and Party B set out from a and B at the same time and walked in opposite directions. Three hours later, they met on the way. It is known that a and B are 24 kilometers apart, and the ratio of their speed is 2:3
11. It is known that there is a distance of 290km between a and B. at present, a car drives from a to B at a speed of 40km / h. 30 minutes after starting, another motorcycle drives from B to a at a speed of 50km / h. how many hours after starting, does the motorcycle meet the car?
12. Xiaodong went to the fruit shop and bought 3 kg of apples and 2 kg of pears for 15 yuan. 1 kg of apples is 0.5 yuan more expensive than 1 kg of pears. How much are apples and pears per kg?
13. Vehicles a and B start from a and B at the same time and travel in opposite directions. A travels 50 kilometers per hour and B 40 kilometers per hour. A reaches the midpoint one hour earlier than B. how many hours does a reach the midpoint?
14. Party A and Party B start from a and B at the same time, face each other and meet in 2 hours. If Party A starts from a and Party B starts from B in the same direction, Party A will catch up with Party B in 4 hours. Given that the speed of Party A is 15 km / h, find the speed of Party B
15. The base of a triangle is 4.3cm long and its area is 17.2cm. How high is it?
16. Xiaoming was 28 years younger than his father last year, and his father's age this year is eight times that of Xiaoming. How old is Xiaoming this year?
17. There are 365 pear and peach trees in the orchard. The number of peach trees is more than twice that of pear trees. How many pear and peach trees are there in the orchard?
18. A car travels for 3 hours on the first day and 5 hours on the second day, 90 kilometers less than the second day. How many kilometers per hour on average?
19. The distance between a and B is 1000 meters. Xiaohua and Xiaoming are facing each other at the same time. Xiaohua walks 80 meters per minute and Xiaoming walks 45 meters per minute?
20. The distance between the two places is 210 kilometers. A and B cars leave each other at the same time. They meet in 3.5 hours. A car travels 28 kilometers per hour. B car travels how many kilometers per hour?
21. The distance between a and B is 189 kilometers. An express train from a to B runs 72 kilometers per hour, and a slow train from B to a runs 54 kilometers per hour. If the two trains start at the same time, the distance between the two trains will be 31.5 kilometers in a few hours?
22. A road construction team has to build a 1680 meter long road. It has been built for 15 days, with an average of 60 meters per day. After the rest of the 12 days, how many meters per day?
23. The school bought 6 tables and 12 chairs for a total of 215.40 yuan, 7.5 yuan for each chair. How much is each table? (first solve the equation, then solve it by arithmetic.)
24. There are 25 baskets of radishes and 32 baskets of cucumbers from the market, weighing 1870 kg. It is known that each basket of radishes weighs 30 kg, and how many kg does each basket of cucumbers weigh?
25. Use two pieces of cloth to make the same suit. The first piece of cloth is 75 meters long, and the second piece is 100 meters long. The first piece of cloth is 10 sets less than the second piece of cloth. How many meters does each suit use?
(1) The average score of Chinese and mathematics in the final examination of Xiaoyang is 96 points, 8 points more than Chinese in mathematics. Chinese is () points, mathematics is () points
(2) There are 42 tons of rice in warehouse A and warehouse B. if 3 tons of rice are transferred from warehouse A to warehouse B, there will be just as much rice in the two warehouses
(3) My father and grandfather were 127 years old in 1994. Ten years ago, my grandfather was 37 years older than my father
(4) In a parking lot, there are 24 cars, including 4 wheels for cars and 3 wheels for motorcycles. There are 86 wheels for these cars, including () motorcycles
(5) The number of students participating in the science and technology group of the children's Palace this year is 35 times less than that of last year, 41 less than that of last year, and there are () students participating in the science and technology group this year
(6) The father is 47 years old and the son is 19 years old
(7) If a tree planting group plants 5 trees per person, there will be 14 trees left; if each person plants 7 trees, there will be 4 trees left. There are () people in this tree planting group, and a total of () trees will be planted

Solutions of the equation 5x + 2x = 1.4 + 0.07

5x+2x=1.4+0.07
7x=1.47
x=2.1
I'm glad to help you. Have a good time~