5) (60a - 30): 5 = 18;
6) 92 + 56 : (14 - b) = 100:
7) (c: 9) • 15 - 47 = 28;
8) (410 – d): 7 + 70 = 120.
​

5) (60а - 30) : 5 = 18

60а - 30 = 18 · 5

60а - 30 = 90

60а = 90 + 30

60а = 120

а = 120 : 60

а = 2

- - - - - - - - - - - -

6) 92 + 56 : (14 - b) = 100

56 : (14 - b) = 100 - 92

56 : (14 - b) = 8

14 - b = 56 : 8

14 - b = 7

b = 14 - 7

b = 7

- - - - - - - - - - - -

7) (c : 9) · 15 - 47 = 28

(с : 9) · 15 = 28 + 47

(с : 9) · 15 = 75

с : 9 = 75 : 15

с : 9 = 5

с = 5 · 9

с = 45

- - - - - - - - - - - -

8) (410 - d) : 7 + 70 = 120

(410 - d) : 7 = 120 - 70

(410 - d) : 7 = 50

410 - d = 50 · 7

410 - d = 350

d = 410 - 350

d = 60