a) 209 - (145 + x - 12) + 96 = 12209 - 145 - x + 12 + 96 = 12170 - x + 108 = 12-x + 278 = 12-x = -15x = 155
Ответ: x = 155
б) 18 + (159 - y) + 34 = 1718 + 159 - y + 34 = 17211 - y + 34 = 17-y + 245 = 17-y = -7y = 73
Ответ: y = 73
a) 209 - (145 + x - 12) + 96 = 12
209 - 145 - x + 12 + 96 = 12
170 - x + 108 = 12
-x + 278 = 12
-x = -15
x = 155
Ответ: x = 155
б) 18 + (159 - y) + 34 = 17
18 + 159 - y + 34 = 17
211 - y + 34 = 17
-y + 245 = 17
-y = -7
y = 73
Ответ: y = 73