3х + 1 = 2(х+4)-5
3х+1=2х+8-5
3х-2х = 8-5-1
х=2
2х+8у+9=10у + 15
2х + 8у -10у=15-9
2х-2у=6
2(х-у)=6
х-у = 3
3х + 1 = 2(х+4)-5
3х+1=2х+8-5
3х-2х = 8-5-1
х=2
2х+8у+9=10у + 15
2х + 8у -10у=15-9
2х-2у=6
2(х-у)=6
х-у = 3