Х+х+х=39 2•(х+1)+3=44 5+2•(х+3х)=35 10х=100 35х=75 решите !

Х+х+х=39
3х=39
х=39:3
х=13
2*(х+1)+3=44
2х+2+3=44
2х=44-2-3
2х=39
х=39:2
х=19.5
5+2*(х+3х)=35
5+2х+6х=35
2х+6х=35-5
8х=30
х=30:8
х=3 3/4
10х=100
х=100:10
х=10
35х=75
х=75:35
х=2 1/7