2) 2a + (a + 2b) - (b - 3a) = 2a + a + 2b - b + 3a = 6a + b

б) 3x - 2(x + 1) + 6(5 - 2x) = 3x - 2x - 1 + 30 - 12x = -11x + 29

в) -3(4 - x) - (7 + 3x) = -12 + 3x - 7 - 3x = -19

3) 2(x + 6) - (3 - 5x) = 0

2x + 12 - 3 + 5x =0

7x + 9 = 0

7x = -9

x = -9/7 = -1 целая 2/7

б) 2(x + 6)(3 - 5x) = 0

2(3x + 18 - 5x² - 30x) = 0

6x + 36 - 10x² - 60x = 0

-10x² - 54x + 36 = 0

10x² + 54x - 36 = 0

5x² + 27x - 18 = 0

D = b² - 4ac = 729 - 4*5*(-18) = 1089 = 33²

x1 = (-27 + 33)/10 = 6/10 = 3/5

x2 = (-27 - 33)/10 = -60/10 = -6

в) 5 - (2x + 4) = 2 + x

5 - 2x - 4 = 2 + x

-2x - x = 2 - 5 + 4

-3x = 1

х = - 1/3

г) 3x - 2(x + 1) = 2 + (5 - x)

3x - 2x - 2 = 2 + 5 - x

x - 2 = 7 - x

x + x = 7 + 2

2x = 9

x = 9/2 = 4 целых 1/2

д) (6x + 8)*2 = 16 + 12x

12x + 16 = 16 + 12x

0 = 0

ответ: бесконечное множество корней. (любые числа)

е) 5x + 4 = 2x - 3,7

5x - 3x = -3,7 - 4

2x = -7,7

x = - 7,7/2 = - 3,85