5.330 Решите уравнение: a) 245 \cdot (m – 33) = 4410; б) 864k – 470k = 5910; в) (3х +12): 72 = 21; г) 420 : (у – 15) = 84.

a) 245 ⋅ (m – 33) = 4410

m - 33 = 4410 : 245

m - 33 = 18

m = 18 + 33

m = 51

Ответ: m = 51

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б) 864k – 470k = 5910

394k = 5910

k = 5910 : 394

k = 15

Ответ: k = 15

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в) (3x + 12) : 72 = 21

3x + 12 = 21 ⋅ 72

3x + 12 = 1512

3x = 1512 - 12

3x = 1500

x = 1500 : 3

x = 500

Ответ: x = 500

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г) 420 : (y – 15) = 84

y - 15 = 420 : 84

y - 15 = 5

y = 5 + 15

y = 20

Ответ: y = 20