How to subtract a specific number using ONLY multiplication or division?

Question

Mathematics

How to subtract a specific number using ONLY multiplication or division?
For example:
a - 30, where 30 is a specific number,
you need to replace the subtraction with some formula to get the same result, but using ONLY multiplication or division.
More specific:
x * 0.002 - 30 = a
We need to get the same result using only multiplication or division. Constants like 0.002 or -30 can be changed to any number, respectively.

Answer 1

No, multiplication and division are higher-level mathematical operations that can be expressed in terms of addition and subtraction and not vice versa.

Answer 2

Well, no, it won't work that way.
a - 30 = x. We cannot find x without knowing a.
First you need to do this subtraction and, if we know a and x, then it is not difficult to find their ratio
a * k \u003d x, where k \u003d a / x)
but why))

Answer 3

It's weird, but it's a simple equation.
a+b=a*k
k=1+b/a
What does it give? We have expressed multiplication in terms of addition. What for? Such a condition.
How can you simplify? If b>>a, then k=b/a. If b is much less than a, then k=1.