решение линейных уровнений

Уравнения идут по столбцам.

Первый

1.

5x = 25

x = 25 : 5

x = 5

2.

-3x = 9

-x = 9 : 3

-x = 3

x = -3

3.

3x = - 15

x = -15 : 3

x = -5

4.

-3x = -27

x = -27 : (-3)

x = 9

5.

4x = 12

x = 12 : 4

x = 3

Второй

1.

5x + 10 = 25

5x = 25 - 10

5x = 15

x= 3

2.

4x + 1 = 13

4x = 13 - 1

4x = 12

x = 3

3.

3x - 4 = 8

3x = 8 + 4

3x = 12

x = 4

4.

6x - 2 = 16

6x = 16 + 2

6x = 18

x = 3

5.

7x + 3 = 17

7x = 17 - 3

7x = 14

x = 2

Третий

1.

7x = 41 - 4x

7x + 4x = 41

11 x = 41

x = 3 8/11

2.

4x = 2x - 9

4x - 2x = -9

2x = -9

x = - 4.5

3.

2x = x - 18

2x - x = -18

x = -18

4.

2x = 6x + 16

2x - 6x = 16

-4x = 16

-x = 4

x = -4

5.

12x = x + 24

12x - x = 24

11x = 24

x = 2 2/11

Четвёртый

1.

8x + 9 = 2x - 80

8x - 2x = - 80 - 9

6x = - 89

x = - 14 5/6

2.

3 - 5x = 40 - 7x

-5x + 7x = 40 - 3

2x = 37

x = 18.5

3.

11 - 3x = x + 15

-3x - x = 15 - 11

-4x = 4

x = -1

5.

6x - 8 = 3x - 4

6x - 3x = -4 + 8

3x = 4

x = 1 1/3

Пятый

1.

2(x - 4) = 15 - x

2x - 8 = 15 - x

2x - x = 15 + 8

x = 23

2.

3(1 - 9x) = 13 - x

3 - 27x = 13 - x

- 28x = 10

x = - 5 / 14

3.

4(2x - 13) = 5 + x

8x - 52 = 5 + x

7x = 57

x = 8 1/7

4.

17 - 4x = 5(x - 7)

17 - 4x = 5x - 35

-9x = -52

x = 9 7/9

5.

6(x - 4) = 5(2 - 3x)

6x - 24 = 10 - 15x

21x = 34

x = 1 13/21

-x^2 - 8x + 12 = 0

x^2 + 8x - 12 = 0

d = 64 + 48 = 112 = 16*7

x12=(-8 +- 4√7)/2 =

x=-4-2√7

x=-4+2√7