Question

Помогите с первым,подалуйста

Answer 1

x - (2x + (3x - (4x + (5x - 7)))) = 11
Начинаем раскрывать изнутри, т.е. справа налево:
x - (2x + (3x - (4x + (5x - 7)))) = x - (2x + (3x - (4x + 5x -7))) = x - (2x + (3x - (9x - 7))) =  x - (2x + (3x - 9x + 7)) = x - (2x + (7 - 6x) = x - (2x + 7 - 6x) = x - (7 - 4x) = x - 7 +4x = 5x - 7 = 11 
5x = 11+7 = 18
x = 18 / 5 = 36 / 10 = 3.6