1 уравнение
7x - 3x = 412
7x - 3x = 4x
412 = 4x
x = 103
2 уравнение
5x + 6x = 231
5x + 6x = 11x
231 = 11x
x = 21
1 уравнение
7x - 3x = 412
7x - 3x = 4x
412 = 4x
x = 103
2 уравнение
5x + 6x = 231
5x + 6x = 11x
231 = 11x
x = 21