Решите уравнение легкое

1) 10x=825
10x=200
x=20010
x=20
2)x20=480080
x20=60
x=2060
x=1200
3)(x-380)50=2000
x-380=200050
x-380=40
x=380+40
x=420
4)(x+8)70=4
x+8=470
x+8=280
x=280-8
x=272
5)640(25-x)=40
25-x=64040
25-x=16
x=25+16
x=41
6)2700(x-12)=90
x-12=270090
x-12=30
x=30+12
x=42

10*х-8*25
10*х=200
х=200:10
х=20
__________
10*20=8*25
200=200