a)(x+27)-12 = 42x+27-12 = 42x+15 = 42x = 42-15x = 27
Ответ: x = 27
б)115-(35+y) = 39115-35-y = 3980-y = 39
Ответ: y = -41
a)
(x+27)-12 = 42
x+27-12 = 42
x+15 = 42
x = 42-15
x = 27
Ответ: x = 27
б)
y = 39-80y = -41115-(35+y) = 39
115-35-y = 39
80-y = 39
Ответ: y = -41