Пошаговое объяснение:
3(2-4х) - 2(5+3х) = 20,
6 - 12х - 10 - 6х = 20,
-12х - 6х = 20 - 6 + 10,
-18х = 24,
х = -24/18,
х = -4/3,
х = -1 1/3