The question of the first year of junior high school, the system of equations, the system of equatio

A fertilizer plant produced a total of 4,300 tons of fertilizer in the first and second quarters, and it is known that the second quarter increased by 15% compared with the first quarter.

Set the production of x tons of fertilizer in the first quarter and y tons of fertilizer in the second quarter, x+y=4300

x+15%x=y

Solve the equation to get x=2000, y=2300

Make up a practical problem in real life, so that the listed equation is: 10x+12(50-x)=560

A class of 50 students went to the countryside to experience life to help fruit farmers pick oranges, a total of 560 were picked, the average number of girls picked 10, the average number of boys picked 12, asked how many female students there were?

Some male and female students have 18 apples, boys have 3 apples, and girls have 2 apples, so how many are these male and female students? [Direct answer to this question].

2 males and 6 females, 4 males and 3 females

If there are a number of boys and girls in a class, and it is known that the number of boys is more than nine-tenths of the girls, and one of the girls is transferred to the boys, the number of boys and girls is exactly equal.

Let the number of girls be x and the number of boys be y

9/10x+3=y

x-1=y+1

Solve equations. x=50

y=48

1.Let the output of the first season be x, then the second season is, and the equation is listed.

x + solution x = 2000 tons, the second season production is 2300 tons.

2.-2x+600=560,x=20

3.2 boys and 6 girls or 4 boys and 3 girls.

4.Suppose a boy x person, a girl y person, y-1=x+1 solution x=48, y=50

The first quarter produces x tons of fertilizer, and the second quarter produces y tons of fertilizer.

x+y=4300 ﹙ 1+15%﹚x=y

x+﹙ 1+15%﹚x=4300

x = 2000 tons.

y = 2300 tons.

A: 2,000 tons of fertilizer were produced in the first quarter and 2,300 tons of fertilizer in the second quarter.

1) If the output in the first quarter is x tons, the output in the second quarter will be tons.

From the meaning of the title, x=2000 tons.

So the second quarter production was 2,300 tons.

2) Let A and B have a total of 50 goods, it is known that A commodity makes a profit of 10 yuan each, and B commodity makes a profit of 12 yuan per piece, and after all of them are sold, A commodity sells a total of x pieces, and the two commodities make a total profit of 560 yuan and asks the value of x.

Let the first season be x, and the second season will be (1+15%)x

x+(1+15%）x=4300

x=2000

1+15%）x=2300

Think about it yourself.。。

Since the same solution, then 2x+5y=-6 3x-5y=16 can form a system of equations. Solution:

x=2,y=-2

Substituting in, we get: 2a+4b=-4,2b+2b=-8 This system of equations gets: b=-2, a=2

First, the values of x and y are obtained by combining the two equations with coefficients.

Substituting the other two equations, synapsing the system of equations about a and b, we can solve the values of a and b. Then you can ask for it.

1.A horse needs x kilograms a day, and a cow needs a kilogram a day (if you haven't learned the binary equations, just express y with x.

8x+15y=162 e.g. y=(5x-3) 75x=7y+3

Solution: x=9, y=6

Omitted. 2.Set up train cars x sections, a total of Y tons of goods.

y=34x+18

y+26=38x

The solution is x=11 and y=392

Omitted. 3.Let Xiao Xue's candle be x cm long, and Xiao Ming's candle be y cm long.

x+y=30

x-10=y-12+6

The solution is x=17 and y=13

Omitted. 4.Type A air conditioner saves x kWh of electricity per day, and Type B air conditioner saves y kWh of electricity per day.

x=y+27

x+ solution gives x=207, y=180

Omitted. 5.I feel that there is something wrong with the topic.

6.Let's say it used to produce x per day.

x+10）*8>200

x+37)*4>(x+10)*8

The solution yields 15 x = 16 answers.

Solution: Suppose a horse needs xkg of hay per day and a cow needs ykg hay per day.

5x-7y=3

8x+15y=162 x=9 y=6

Solution: Suppose a horse needs xkg hay per day, and a cow needs ykg hay per day

8x+15y=162

5x-7y=3 yields: x=9, y=6

2.Set up train carriages x sections, a total of Y tons of goods, according to the meaning of the topic:

y=34x+18

y+26=38x

The solution is x=11 and y=392

3.Set Xiaoxue candle length x cm, Xiao Ming's candle length Y cm, according to the title:

x+y=30

x-10=y-12+6

The solution is x=17 and y=13

4.A air conditioner saves x degrees of electricity per day, and B air conditioner saves y degrees of electricity per day

x=y+27

x+ solution gives x=207, y=180

5.If it costs $x to buy a piece of A, $y to buy a piece of B, and $z yuan to buy a piece of A and C, then there are:

3x+y=315...1)

4x+10y+z=420...2)

Substituting (1) into x=(315-y) 3 into (2) yields:

3z=-26y, no solution.

6.Set the original production of x per day, according to the meaning of the topic:

x+10）*8>200

x+37)*4>(x+10)*8

The solution is 15 x = 16

Solution: Set 600m of fabric to make x sets of school uniform chain loss.

It can produce fabrics for tops.

pants so x=240

x = 240 A: 600m of cloth is produced with 360m....The ruler calls the faction....Ryga.

Untie; Set up the production of x pieces, which are derived from the title;

Solution: Solution 1: Set the unit price of radish last month is x yuan catty, and the unit price of pork ribs is y yuan catty, according to the title:

3x+2y=36

3(1+50%)x+2(1+20%)y=45 Solution:

x=2y=15

The unit price of radish on this day is (1+50%)x=(1+50%) 2=3, and the unit price of pork ribs on this day is (1+20%)y=(1+20%) 15=18, A: The unit price of radish on this day is 3 yuan catty, and the unit price of pork ribs is 18 yuan catty;

Solution 2: The unit price of radish on this day is x yuan catty, and the unit price of pork ribs is y yuan catty, according to the title:

31+50%x+2

y=363x+2y=45

Solution: x=3

y=18 Answer: The unit price of radish on this day is 3 yuan catty, and the unit price of pork ribs is 18 yuan catty.

Solution: Set the unit price of radish last month is x yuan catty, and the unit price of pork ribs is y yuan catty, according to the title:

3x+2y=36

3 (1 + 50%) x + 2 (1 + 20%) y = 45 solution is: x = 2

y=15The unit price of radish on this day is (1+50%)x=(1+50%) 2=3, the unit price of pork ribs on this day is (1+20%)y=(1+20%) 15=18, A: The unit price of radish on this day is 3 yuan catty, and the unit price of pork ribs is 18 yuan catty;

Set the unit price of radish on this day to be x yuan catty.

The unit price of pork ribs is Y yuan catty.

The system of column equations is.

3x+2y=45

3x (1+50%) + 2y (1+20%) = 36 solutions to the system of equations.

x=3 yuan catty.

y=18 yuan jin.

1 formula x3 gives 6x+9y=36 as three formulas.

2 formula x2 gives 6x+8y=34 is four formulas.

Three formula minus four formula to get y=2

Bring y=2 into equation 1 to get x=3

Convert the x of formula 1 to x 12 3y 2, and then substitute x into formula 2 to find y.

Hello, 2x+3y=12

3x+4y=17②

Let 4* -3*: 8x-9x=12*4-17*3=-3=-x, so x=3, and y=2

So x=3, y=2 thanks

Multiply 1 by 3/2 and subtract 2 to get the solution.

I enlarge 1 by 3 times and 2 by 2 times.

Then subtract 2 from the formula of 1

Derive the value of y.

Then substitute for x

First, calculate the values of x and y, and solve x=2 and y=1

Then, substituting the values of x and y into mx ny=8 and mx ny=4 gives 2m+n=82m-n=4

The solution yields m=3 and n=2