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Simple math problems in the first day of junior high school
1、x-(x- 1)/2=2-(x-2)/3

x-x/2+ 1/2=2-x/3+2/3

x/2+x/3=2+2/3- 1/2

5x/6= 13/6

x= 13/5

2 、( x- 1)/2-(2x-7)/6 =(4x-5)/3- 1

x/2- 1/2-x/3+7/6 = 4x/3-5/3- 1

7/6- 1/2+ 1+5/3 = 4x/3+x/3-x/2

10/3=7x/6

x=30/7

3、3(2x- 1)= 2( 1-x)- 1

6x-3=2-2x- 1

8x=2- 1+3

8x=4

x= 1/2

4、 1-(6-x)/6 = 0.4[ 1+( 1+2x)/4]

1-( 1-x/6)= 0.4+0. 1 *( 1+2x)

1- 1+x/6 = 0.4+0. 1+0.2x

x/6-0.2x=0.5

-x/30=0.5

x=- 15

5、 15-(8-5x)=7x+(4-3x)

15-8+5x=7x+4-3x

5x+3x-7x=4+8- 15

x=-3

6 、( 3x+ 1)/2-2 =(3x-2)/ 10-(2x+3)/5

3x/2+ 1/2-2 = 3x/ 10- 1/5-2x/5-3/5

3x/2-3x/ 10+2x/5 = 2- 1/5-3/5- 1/2

8x/5=7/ 10

x=7/ 16

7、7(2x- 1)-3(4x- 1)= 4(3x+2)- 1

14x-7- 12x+3 = 12x+8- 1

14x- 12x- 12x = 8- 1-3+7

- 10x= 1 1

x=- 1 1/ 10

8、2(x-2)-3(4x- 1)+9( 1-x)

2x-4- 12x+3=9-9x

2x- 12x+9x=9-3+4

-x= 10

x=- 10

9、y-(y- 1)/2=2-(y+2)/5

y-y/2+ 1/2=2-y/5-2/5

y-y/2+y/5=2-2/5- 1/2

7y/ 10 = 1 1/ 10

y= 1 1/7

10 、( 0.4x+0.9)/0.5-(0.03+0.02 x)/0.03 =(x-5)/2

4x/5+0.45- 1-2x/3=x/2-5/2

4x/5-2x/3-x/2= 1-5/2-0.45

- 1 1x/30=-39/20

x= 1 17/22

1 1、2x+(3x- 1)= 16-(x+ 1)

2x+3x- 1 = 16-x- 1

5x+x= 15+ 1

6x= 16

x=8/3

12 、( x-3)/2-(4x+ 1)/5= 10

x/2-3/2-4x- 1/5= 10

-7x/2= 10+ 1/5+3/2

-7x/2= 1 17/ 10

x=- 1 17/35

13 、( x-3)/0.5-(x+4)/0.2= 1.6

2x-6-5x-20= 1.6

-3x=27.6

x=-9.2

14 、[ 2(x+ 1)]/3 = {[5(x+ 1)]/6 }- 1

2x/3+2/3=5x/6+5/6- 1

2x/3-5x/6=5/6- 1-2/3

-x/6=-5/6

x=5

15 、( 0. 1x-02)/0.2-(x+ 1)/0.5+x

There is no equation. .

16 、( 2x- 1)/6-(5x+ 1)/8 = 1

x/3- 1/6-5x/8- 1/8 = 1

-7x/24 = 1+ 1/8+ 1/6

-7x/24=3 1/24

x=-3 1/7

17 、( 3+x)/2-(2x+3)/3 =(3x+ 1 1)/6

3/2+x/2-2x/3- 1 = x/2+ 1 1/6

-x/6-x/2 = 1 1/6-3/2+ 1

-2x/3=4/3

x=-2

18、5(x+2)=2(5x- 1)

5x+ 10= 10x-2

-5x=- 12

x= 12/5

19、7(2x- 1)-3(4x- 1)= 4(3x+2)- 1

14x-7- 12x+3 = 12x+8- 1

2x-4= 12x+7

- 10x= 1 1

x=- 1 1/ 10

20、3(x-7)+5(x-4)= 15

3x-2 1+5x-20= 15

8x-4 1= 15

8x=56

x=7