г) (40.x): 10 = 28 y: 9-28 = 32 39 + 490 : a = 46 (25-a).7 = 63 400:b-32 = 48

Решим уравнения и сделаем проверку.

(40 ⋅ x) : 10 = 28

40 ⋅ x = 28 ⋅ 10

40 ⋅ x = 280

x = 280 : 40

x = 7

Проверка:

(40 ⋅ 7) : 10 = 28

280 : 10 = 28

28 = 28

Ответ: x = 7

---

y : 9 - 28 = 32

y : 9 = 32 + 28

y : 9 = 60

y = 60 ⋅ 9

y = 540

Проверка:

540 : 9 - 28 = 32

60 - 28 = 32

32 = 32

Ответ: y = 540

---

39 + 490 : a = 46

490 : a = 46 - 39

490 : a = 7

a = 490 : 7

a = 70

Проверка:

39 + 490 : 70 = 46

39 + 7 = 46

46 = 46

Ответ: a = 70

---

(25 - a) ⋅ 7 = 63

25 - a = 63 : 7

25 - a = 9

-a = 9 - 25

-a = -16

a = 16

Проверка:

(25 - 16) ⋅ 7 = 63

9 ⋅ 7 = 63

63 = 63

Ответ: a = 16

---

400 : b - 32 = 48

400 : b = 48 + 32

400 : b = 80

b = 400 : 80

b = 5

Проверка:

400 : 5 - 32 = 48

80 - 32 = 48

48 = 48

Ответ: b = 5