7х/6 = 49/14
7х * 14 = 49 * 6
7х * 14 = 294
7х = 294 : 14
7х = 21
х = 21 : 7
х = 3
----------------------
7 * 3 /6 = 49/14
21/6 = 49/14
7/2 = 7/2
3,5 = 3,5
8/13 = 2х/39
2х * 13 = 8 * 39
2х * 13 = 312
2х = 312 : 13
2х = 24
х = 24 : 2
х = 12
-----------------------
8/13 = 2 * 12/39
8/13 = 24/39
8/13 = 8/13
2/3 = 28/7х
7х * 2 = 28 * 3
7х * 2 = 84
7х = 84 : 2
7х = 42
х = 42 : 7
х = 6
--------------------
2/3 = 28/7*6
2/3 = 28/42
2/3 = 2/3
9/10 = 63/5*(х+8)
9/10 = 63/5х+40
9*(5х+40) = 63 * 10
45х + 360 = 630
45х =630 - 360
45х = 270
х = 270 : 45
х = 6
--------------------------
9/10 = 63/5*(6+8)
9/10 = 63/5*14
9/10 = 63/70
9/10 = 9/10
0,9 = 0,9