Question

2x - 9 = 12 3x + 12 = 3427x : 9 = 334x * 2 = 129

Answer 1

Решение уравнений:

№ 1

2x - 9 = 12

2х = 12 + 9

2х = 21

х = 21 : 2

х = 10,5

_____

(10,5 * 2) - 9 = 12

21 - 9 = 12

12 = 12

Всё верно!

Ответ: х = 10,5

№ 2

3x + 12 = 34

3х = 34 - 12

3х = 22

х = 22 : 3

х = 22/3

x = 7 1/3

______

(7 1/3  * 3) + 12 = 34

22 + 12 = 34

34 = 34

Всё верно!

Ответ: x = 7 1/3

№ 3

27x : 9 = 3

27х = 3 * 9

27х = 27

х = 27 : 27

х = 1

______

(1 * 27) : 9 = 3

27 : 9 = 3

3=3

Всё верно!

Ответ: х = 1

№ 4

34x * 2 = 129

34х = 129 : 2

34х = 129/2

х = 129/2 : 34

х = 129/2 * 1/34

х = (129 * 1) / (2 * 34 )

х = 129 / 68

x = 1 61/68

_______

(1 61/68 * 34) * 2 = 129

64 1/2 * 2 = 129

129 = 129

Всё верно!

Ответ: x = 1 61/68

Answer 2

It looks like you've provided a series of equations. Let's solve them one by one:

1. $2x - 9 = 12$: Add 9 to both sides: $2x = 21$ Divide both sides by 2: $x = 10.5$

2. $3x + 12 = 342$: Subtract 12 from both sides: $3x = 330$ Divide both sides by 3: $x = 110$

3. $7x : 9 = 33$: Multiply both sides by 9: $7x = 297$ Divide both sides by 7: $x = 42.43$ (approximately)

4. $4x * 2 = 129$: Divide both sides by 2: $4x = 64.5$ Divide both sides by 4: $x = 16.125$

So, the solutions for the respective equations are approximately:

1. $x = 10.5$
2. $x = 110$
3. $x \approx 42.43$
4. $x \approx 16.125$