Verified answer

.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.

Ответ:

Объяснение:

1)

5х - (2х - 9) = 12

5х - 2х + 9 = 12

3х = 12 - 9

3х = 3

х = 3 : 3

х = 1

2)

5х - 6(2х + 7) = 13 - (х + 1)

5х - 12х - 42 = 13 - х - 1

5х - 12х + х = 13 - 1 + 42

-6х = 54

х = 54 : (-6)

х = -9

3)

12 + 4 * (t - 3) - 2t = (5 - 3t) + 9

12 + 4t - 12 - 2t = 5 - 3t + 9

4t - 2t + 3t = 5 + 9 - 12 + 12

5t = 14

t = 14 : 5

t = 2,8

4)

(2х +3)/2 = (х + 2)/3 - (1 - х)/4

6*(2х + 3) = 4(х + 2) - 3(1 - х)

12х + 18 = 4х + 8 - 3 + 3х

12х - 4х - 3х = 8 - 3 - 18

5х = -13

х = - 13 : 5

х = - 2,6

5)

(3х + 2) * (3х - 1) = (3х - 4)²

(3х + 2) * (3х - 1) = (3х - 4) * (3х - 4)

9х² - 3х + 6х - 2 = 9х² - 12х - 12х + 16

9х² - 9х² - 3х + 6х + 12х + 12х = 16 + 2

27х = 18

х = 18 : 27

х = 2/3