(7а-а)×8=80 (15в+в): 4=8 14у-2у+76=100 24х-15х+47=1919 6х+25х=1674 (30000-408×25)×(609×700-417-417295)= решите !

1)(7a-a)*8=80
6a*8=80
48a=80
a= 3/5
2) (15в+в):5=8
16в:5=8
16в=5*8
16в=40
в=2/5
3) 14y-2y+76=100
12y=100-76
12y=24
y=2
4)24x-15x+47=1919
9x=1919-47
й=1872
x=208
5)6x+26x=1674
32x=1674
x=52 целых 10/32
х=52 целых 5/16
6) (30000-408*25)*(609*700-414-417295)=170101800
1. 408*25=10200
2.30000-10200=19800
3. 609*700=426300
4.426300-414=425886
5.425886-417295=8591
6.19800*8591=170101800