Solve the unary quadratic square type problem 10

Solution: If Liu Wei planted x trees and Zhang Qiang planted x+15 trees, then x+(x+15)=75

Solution, x = 30 trees.

So the number of trees planted by Zhang Qiang: x+15=45.

Set the train speed x kilotolia liquid and know the meter buried per hour.

15/3600*(x+

15x+15*

2x=32*

x = train tremor: 17 3600 * (km.)

Solution: Set the age of death to be x years old.

Then the son lived x 2 years old.

Age at the time of marriage: x 6+x 12+x 7

The age of the son at birth is: (x 6+x 12+x 7+5) according to the meaning of the equation:

x 6 + x 12 + x 7 + 5) + x 2 + 4 = x solution x = 84 (years).

The age of marriage is: 84 6 + 84 12 + 84 7 = 33 (years).

Asked on Huaying Online, the result was 81

Let's say his age of death is x

Then 1 6x+1 12x+1 7x+5+1 2x+4=x gives x=84 the age at which he died.

Age of marriage = 1 6x + 1 12x + 1 7x = 31

Set the whole age x

1/6x+1/7x+1/12x+5+1/2x+4=xx=84

Age at the time of marriage (1 6 + 1 12 + 1 7) 84 = 33

Solution: Shediphantu lived to be x years old.

1/6x+1/12x+1/7x+5+1/2x+4=x75/84x+9=x

9=9/84x

x=84

Let's say you're 4 years older than your sister and you'll be twice as old next year.

Solution: Suppose your age is x years old, then your sister's age is (x-4) years old, according to the title, x+1=2(x-4+1), solve x=7.

A: Your age is 7 years old, and your sister's age is 7-4=3 years old.

There are 34 apples on the table, and Xiao Ming's number of apples is twice that of Xiao Hong, and he asks him how many apples there are. Solution: Let Xiaohong have y apples, then Xiao Ming has 2y+1, y+(2y+1)=34, that is, 3y+1=34, y=11

1, from 7-x=13, we get -x=13-7, that is, x=7-132, from 5x=4x+8, we get 5x-4x=8, that is, x=83, from 1 2x=1, we get 2x=1

4, from x-(2+3x)=1, get x-2-3x=15, from x-(2+3x)=1, get x-2-3x=16,., .,From 10(1 5x-2)=25(8 5x+3 25)-2, we get 40 x+1=2 x-20, i.e., x=-38 21

(1) Solution: Set x days later.

Then: 200 + 15x = 80 + 25x

120=10x

x = 122) solution: let the original price be x yuan.

Then: x-80%x=20

20%x=20 upstairs is 80 (actual after discount).

x=100100-20=80 (yuan).

3) Solution: Let the sales amount be x yuan.

Then: 800+

x=35000

4) Solution: If each car can sit x people, now each car can sit (x+10) people.

Then: 20x+20=16(x+10).

20x-16x=160-20

4x=140

x=3535*20+20=720 (person).

Added -3x+7

1.False 2Wrong.

3.False 4Wrong.

5.False 6Wrong.

1.From 7-x=13, we get x=13-7 False, is x=7-13

2.From 5x=4x+8, we get 5x+4x=8 False, is 5x-4x=8

3.From 1 2x=1, we get x+1 2 wrong, which is 2x=1 1

4.From x-(2+3x)=1, we get x-2+3x=1 False, is x-2-3x=1

5.From x-(2+3x)=1, we get 5x-40+33=-6x-5 false, 6From 10 (1 5x-2) = 25 (8 5x+3 25)-2, get 2x-20 = 40x+3-50 grass, you don't want to see so simple, you can be wrong so personal, you can only sympathize with your teacher...

1. If the monthly interest rate of the demand deposit is x%, then according to the topic, 1000 (1 + 2% 80%) + 1000 (1 + 12 x% 80%) will be obtained

Solve this equation to get x

2 Solve the number in the single digit is x, then the number in the ten digit is x+2, and the number in the hundred digit is x-2

According to the title, got.

17[(x-2)+(x+2)+x]=100(x-2)+10(x+2)+x

Solve the equation to get x=3

x+2=5,x-2=1

A: This three-digit number is 153

3. Solve the two-digit number composed of two numbers on the high position as x, then the two-digit number composed of the two numbers on the low position is 5x+4; According to the title, got.

100(5x+4)+x]-[100+(5x+4)]=7920

Solve the equation and get.

x=19 5x+4=99

A: The original four-digit number was 1999