надеюсь
Пошаговое объяснение:
1) x + 4/15 = 2/3 + 2/5
x + 4/15 = 16/15
x = 16/15 - 4/15
x = 4/5.
2) y - 5/20 = 5/8 - 3/10
у - 1/4 = 13/40
y = 13/40 + 1/4
y = 23/40.
3) 2/3 - (7/9 - a) = 1/3
2/3 - 7/9 + а = 1/3
- 1/9 + а = 1/3
а = 1/3 + 1/9
а = 4/9
4) х + 4/15 = 2/3 + 2/5
х + 4/15 = 16/15
х = 16/15 - 4/15
х = 4/5
