Номер 519

Розв’яжіть рівняння:

1) 8 (x – 14) = 56
x – 14 = 56 : 8
x – 14 = 7
x = 7 + 14
x = 21
8 · (21 – 14) = 56
56 = 56

2) (46 – x) · 19 = 418
46 – x = 418 : 19
46 – x = 22
x = 46 – 22
x = 24
(46 – 24) · 19 = 418
418 = 418

3) 9 (143 – 13x) = 234
143 – 13x = 234 : 9
143 – 13x = 26
13x = 143 – 26
13x = 117
x = 117 : 13
x = 9
9 · (143 – 13 · 9) = 234
234 = 234

4) 17 (5x – 16) = 238
5x – 16 = 238 : 17
5x – 16 = 14
5x = 14 + 16
5x = 30
x = 30 : 5
x = 6
17 · (5 · 6 – 16) = 238
238 = 238