5(1-3х)=20 и
3(2х-1)=9и
6(3-2х)=42
5(1-3х)=20
1-3х=20/5
1-3х=4
-3x=3
x=-1
3(2х-1)=9
2х-1=9/3
2х-1=3
2х=3+1
2x=4
x=2
3-2х=42/6
3-2х=7
-2x=7-3
-2x=4
x=-2
5(1-3х)=20 3(2х-1)=9 6(3-2х)=42
5-15х=20 6х-3=9 18-12х=42
-15х=20-5 6х=9+3 -12х=42-18
-15х=15 6х=12 -12х=24
х=-1 х=12:6 х=-2
х=2