решить самостоятельную 6 класс

Пошаговое объяснение:

2x = 18 - x

2x + x = 18

3x = 18

x = 6

7x + 3 = 30 - 2x

7x+2x = 30 - 3

9x = 27

x = 3

7 - 2x = 3x - 18

3x + 2x = 7+18

5x = 25

x = 5

0,2x + 2,7 = 1,4 - 1,1x

0,2x + 1,1x = 1,4 - 2,7

1,3x = -1,3

x = -1

5,4 - 1,5x = 0,3x - 3,6

0,3x + 1,5x = 5,4 + 3,6

1,8x = 9

x = 5

(3/8)x + 15 = (1/6)x + 10

(3/8)x - (1/6)x = 10 - 15

(9/24)x - (4/24)x = -5

(5/24)x = -5

x = -5 * 24/5

x = -24

3(x - 2) = x + 2

3x - 6 = x+2

3x - x = 2+6

2x = 8

x = 4

5 - 2(x - 1) = 4 - x

5 - 2x + 2 = 4 - x

7 - 2x = 4 - x

2x - x = 7 - 4

x = 3

(7x + 1) - (9x + 3) = 5

7x + 1 - 9x - 3 = 5

-2x - 2 = 5

2x = -2 - 5

2x = -7

x = -3,5

3,4 + 2y = 7(y - 2,3)

3,4 + 2y = 7y - 16,1

7y - 2y = 3,4 + 16,1

5y = 19,5

y = 3,9

0,2(7 - 2y) = 2,3 - 0,3(y - 6)

1,4 - 0,4y = 2,3 - 0,3y + 1,8

1,4 - 0,4y = 4,1 - 0,3y

0,4y - 0,3y = 1,4 - 4,1

0,1y = -2,7

y = -27

2/3*(1/3x - 1/2) = 4x + 2 1/2

(2/9)x - 1/3 = 4x + 2 1/2

4x - (2/9)x = -1/3 - 2 1/2

(3 7/9)x = -2/6 - 2 3/6

(3 7/9)x = -2 5/6

x = -2 5/6 : 3 7/9

x = -17/6 * 9/34

x = -3/4

4(5x + 2) = 10(2x - 3) + 15

20x + 8 = 20x - 30 + 15

20x + 8 = 20x - 15

20x - 20x = -15-8

0 ≠ -23

уравнение не имеет решений

2(7x - 7) = 7(2x - 3) + 7

14x - 14 = 14x - 21 + 7

14x - 14 = 14x - 14

14x - 14x = 7 - 7

0 = 0

x є (-∞ ; ∞)

уравнение имеет множество решений