2х +82 = 180
2х = 180 - 82
х = 98 :2
х = 49
х + х + 20 +62 = 180
2х +20 + 62 = 180
2х =98
х = 98 : 2
х =49
проверка :
49 +49 +20 +62=180
180 =180
2х +82 = 180
2х = 180 - 82
х = 98 :2
х = 49
х + х + 20 +62 = 180
2х +20 + 62 = 180
2х +82 = 180
2х = 180 - 82
2х =98
х = 98 : 2
х =49
проверка :
49 +49 +20 +62=180
180 =180