4x + 3(x + 20) = 9(x - 10)4x + 3x + 60 = 9x - 907x + 60 = 9x - 9060 + 90 = 9x - 7x150 = 2xx = 150/2x = 75
Ответ: x = 75.
4x + 3(x + 20) = 9(x - 10)
4x + 3x + 60 = 9x - 90
7x + 60 = 9x - 90
60 + 90 = 9x - 7x
150 = 2x
x = 150/2
x = 75
Ответ: x = 75.