dimochka3777 1)
(1 142 600 - 890 778) / 74 + 309*708
 251 822 / 74 = 3 403
3 403 + 218 772 = 222 175

13^2 + (52 - 49)^3 = 169 + 3^3 = 169 + 27 = 196

2)
12a = 204
a = 17

5y = 315
y = 63

3)
x + 3x = 168
4x = 168
x = 42

4)
147 + 23x + 39x 
62x + 147
x = 3
186 + 147 = 333
x = 10
620 + 147 = 767

5) x(5+10) = 120
15x = 120
x = 8
8*5 + 8*10 = 120
Ответ 8 по 5 и 8 по 10