Rishi Garg 13th Jul, 2020

Function f(x) = 9x is a linear function and continuously increasing function. This function does not have any minimum or maximum until unless the domain is not specified. For example if domain is [a, b] for some a and b then local maximum over this interval is b and local minimum over this interval is a.

So, the given function does not have any minimum or maximum unless the domain is specified.

Hope it helps.