Question

5. Multiply a by 3, subtract 1..
(a X 3) - 1 = b
Input, a
Output, b

Answer 1

Unless you know what the value of a and b is, there is no way to solve for simplify the problem. You have already done the problem with the answer:
3a-1=b

You can not simplify this anymore without the values of a and/or b.

Answer 2

Explanation:

1.3a-1=b

2.3a=b+1

3.3a=2b