Подскажите решение 1) 3*620-x=54200 2) 63: (14-f)=7 3) 3*a-7=14 4) 875*4-x=2600

1) 3*620-x=54200
1860 - x = 54200
- x = 54200 - 1860
- x = 52340
x = -52340

2) 63/(14-f) = 7
14-f = 63/7
14-f=9
-f=9-14
-f=-5
f=5

3) 3a-7=14
3a=21
a=21/7
a=3

4) 875*4-x=2600
3500 - x = 2600
-x = 2600-3500
-x = -900
x=900