Congruence Relations Given 3 positive integers a, b, and n (whose maximum values are the maximum representable integer value in your language), output a truthy value if a ≡ b (mod n), and falsey otherwise. For those unfamiliar with congruency relations, a ≡ b (mod n) is true iff a mod n = b mod n (or, equivalently, (a - b) mod n = 0).
Restrictions

Built-in congruence testing methods are forbidden
Built-in modulo operations are forbidden (this includes operations such as Python's divmod function, which return both the quotient and the remainder, as well as divisibility functions, residue system functions, and the like)

Test Cases
(1, 2, 3) -&gt; False
(2, 4, 2) -&gt; True
(3, 9, 10) -&gt; False
(25, 45, 20) -&gt; True
(4, 5, 1) -&gt; True
(83, 73, 59) -&gt; False
(70, 79, 29) -&gt; False
(16, 44, 86) -&gt; False
(28, 78, 5) -&gt; True
(73, 31, 14) -&gt; True
(9, 9, 88) -&gt; True
(20, 7, 82) -&gt; False

This is code-golf, so shortest code (in bytes) wins, with earliest submission as a tiebreaker.
Jelly, 5 bytes

_ÆD⁵e


Making heavy use of Anything else that is not forbidden is allowed. 

Try it online!

How it works

_ÆD⁵e  Main link. Left input: a. Right input: b. Additional input: n

_      Subtract b from a.
 ÆD    Compute all divisors of the difference.
   ⁵e  Test if n is among the divisors.