Question

For what value of the constants A and B is the function (ax+3) continuous for all X if x > 5?

Answer 1

`f(x)=ax+b` is continuous for all Real (in fact all Complex) constant values of `a` and `b`

Explanation:

The question is not clear but I have assumed:

`color(white)("XXX")(ax+3)` was meant to be `(ax+b)`

`color(white)("XXX")`capitalization of `A, B, and X` is irrelevant.
`color(white)("XXX")(A -=a), (B-=b), and (X-=x)`

Any function of the form `f(x)=ax+b` with constant values `a` and `b` is a linear function which is continuous for all values of `x`.
(The limitation `x > 5` does not seem to be relevant).