Find a fractional equation for a one to simple eighth grade math one dimensional equation

Let's set the number of yogurt bottles we bought for the first time to x bottles, and the number of bottles we bought for the second time is x+3 5x=bottles; The first time you use yuan, then the price of each bottle is the price of each bottle, and the second time you use yuan, the price of each bottle is the price of each bottle; The price of each bottle bought this time is the same as the price of the first time, so the equation is easy to list.

Set: Bought x bottles of yogurt for the first time. Solution: Multiply both sides by x, get: 20x = square Divide each term by x to get:

20=x=5 bottles.

A: Bought 5 bottles of yogurt for the first time.

Set up a bottle of yogurt for x yuan in the supply and marketing building, and bought a bottle of yogurt for the first time.

xy= (obtained by 2 by 1*.)

Obtained by 4-3.

y=5x=A: 5 bottles.

Let's do it with binary at once, it should be right.

Set up a bottle of yogurt for x yuan in the supply and marketing building, and bought a bottle of yogurt for the first time.

xy= 12 by 2 to 3

4 from 1*

Obtained by 4-3.

y=5x=A: 5 bottles.

The first time the quantity is x, x = 5, the first time I bought 5 bottles.

Set up x students in the first year of junior high school and y students in the first year of high school.

Then the system of simultaneous equations is as follows:

x+y=500

1+20%)x+(1+15%)y=(1+18%)*500 solves the system of equations to obtain: x=300, y=200

Therefore, the enrollment of the first year of junior high school = (1 + 20%)*300 = 360 people, and the enrollment of the first year of high school = (1 + 15%)*200 = 230 people.

Set the first x at the beginning and one y at the high level.

x/(1+ (1)

x+y=500*(1+ (2)

y=590-x from (2);

Bring in (1) to:

y=360，x=230

Set the number of students enrolled in the first year of last year x the number of students enrolled in the first year of high school y

x+y=500

1+20%)x+(1+15%)y=500*(1+18%), x=300 y=200

At the beginning of this year, the first move is 300 * (1 + 20%) = 360

200 * (1 + 15%) = 230

Solution: Set up x students in the first year of junior high school and y students in the first year of high school.

x+y=500

1+20%)x+(1+15%)y=(1+18%)*500: x=300, y=200

A: There are 360 students in the first year of junior high school and 230 people in the first year of high school.

Solution: Set the number of students enrolled in the first year of junior high school as x and the number of students enrolled in the first year of high school as y people {x+y=500

1+20%)+1+15%)=500*(1+18%), according to the binary system, we can get x=300, y=200

If the enrollment in the first year of junior high school is x, and the enrollment in the first year of high school is y, then there is x+y=500

According to the title: x(1+20%)+y(1+15%)=500 (1+18%);

Simultaneous solution, x=300, y=200

Solution: The original plan was to sow x acres of wheat every day.

2000÷x=(2000+240)÷(x+30)2000x+60000=2240x

240x=60000

x=2502000/x=2000/250=8

A: The original plan was to sow 250 acres of wheat every day, but the original plan was to sow 8 days.

Assuming that the original plan is to sow x mu every day, 2000 x = (2000 + 240) (x + 30) solution to get x = 250

After testing, it is the solution of the listed equation and conforms to the title.

2000 x = 8 (days) A:

The first two items are divided.

2x+6)(x-3)/(x+3)(x-3)x+3)/(x-3)(x+3)2/x

The first two items are combined:

2x+6)(x-3)-(x+3)] x-3)(x+3)(2x 2-18-x-3) (x-3)(x+3)(2x 2-x-21) (x-3)(x+3)(2x-7)(x+3) (x-3)(x+3)--cross multiplication.

2x-7)/(x-3)

2+1/(x-3)

Substitution in the original form. 2+1/(x-3)-2/x=2

i.e. 1 (x-3)-2 x=0

Go to the denominator. x-2(x-3)=x(x-3)

x(x-3)-x+2(x-3)=0

Merge. x^2-2x-6=0

Recipe issues. x^2-2x+1=7

x+1)^2=7

x+1= root number 7

The original equation has two sets of solutions:

x=- root number 7-1

Or. x=root number 7-1 Question 2:

min=2/3

The speed of the bicycle is set to x kilometers per hour.

Car speed: 3x

km/h15/x=15/3x+2/3

Denominator x15 = 5 + 2 3x

The solution is x=15

The speed of the bike is 15km h

Question 3: Move the term first, you can find an interesting phenomenon, which is also the key to obtaining a simple solution.

1 (x+5)-1 (x+6)=1 (x+7)-1 (x+8). (x+6)-(x+5)]/x+6)(x+5)=…Leave it alone, no change anyway)

Merger. 1 (x+5)(x+6)=1 (x+7)-1 (x+8) does the same thing with the right.

1 (x+5)(x+6)=1 (x+7)(x+8)x+5)(x+6)=(x+7)(x+8)--cross-multiplication.

Remove the brackets from the first of the pure forest and get the spring stool x=-13 2

From the question, we can see that a=3-2b is substituted into the second formula.

2b=2-2a=2-2(3-2b)=2-6+4b6b=4

b=2/3a=3-4/3=5/3

1) Deformation simplification: a+2b-3=0

2) Deformation simplification: a-b-1=0

1)-2) gets: 3b=2

b = 2 3 substituted by 2): a-2 3-1 = 0

a=5/3

b(1-3).This is generally not the case in equations, unless it is a column equation solution problem. Is there anything wrong with that?

Solution: The original plan was to complete x sets per day; 3000/（x+20%x）+4=3000/x

Simplifying,solution, x=125