1)
[tex]x = 2k+1\\\\-2k = 1 - x \ \ /:(-2)\\\\k = \frac{x-1}{2}[/tex]
2)
[tex]2k = 7n+5\\\\-7n = 5-2k \ \ /:(-7)\\\\n = \frac{2k-5}{7}[/tex]
3)
[tex]t = \frac{1}{a}-5xa\\\\5xa = \frac{1}{a}-t\\\\5xa = \frac{1-at}{a} \ \ /:5a\\\\x = \frac{1-at}{5a^{2}}[/tex]
