30 - 5х = 25х
-5х - 25х = -30
-30х = -30
х = 1
--------------------
3х - 13 = 21
3х = 21 + 13
3х = 34
х =
-------------------------
3 + 4х = 5 + 6х
4х - 6х = 5 - 3
-2х = 2
х = -1
30 - 5х = 25х
-5х - 25х = -30
-30х = -30
х = 1
--------------------
3х - 13 = 21
3х = 21 + 13
3х = 34
х =
-------------------------
3 + 4х = 5 + 6х
4х - 6х = 5 - 3
-2х = 2
х = -1