A tessellation has no A) gaps or overlaps, as a tessellation is all about repeated figures, which can be translated onto other figures, this produces a pattern.<span />

is undefined where the denominator is zero. The domain is all values of x for which the function is defined.
The domain of f(x) is all real numbers except 13.
As long as the number plugged in Times 15 is less than 180, it works
Here are your three values: 1,2,3