Your problem; 6/13 = 3/c
Your work ⬇️
6/13 - 3/c = 0
⬆️
simplify
6/13 - 3/c
⬆️
simplify
3 ÷ c = 3c
6 ÷ 13 = 0.46153
Lowest common denominators⬇️
Right denominator: c
Left denominator: 13
LCD: 13c
6(c) - 39 / 13c
End of this step ⬆️
6(c) - 39 / 13c
3(2)(c) -13 / 13c
2c = 13
+13. +13
-----. ----
15c 26
÷ 2. ÷ 2
------. ------
7.5c 13
The numerator of "c" would be 13
good luck!
SO, c = 13 / 2