# Where can I find a calculator for constrained optimization of general form of algebraic equation?

I'm working with a fairly complex equation and I need to carry out constrained optimization of the same. The first order differential equations are very messy to solve by hand and hence I thought to use online calculators. Problem with calculators like wolfram is that I cannot choose the variables with respect to which optimization needs to be done. If I use numbers in place of other variables it would defy the purpose. Are there any calculators available online for the problem I have? I am open to use coding based software like Matlab.

For example:
Maximize $$\ ax^b−x$$
w.r.t $$\ x$$
s.t. $$\ x>0,a>1,0
The original problem is multivariable and much more complex. I don't want to optimize with specific values for a,b.

You can set the decision variables in Wolfram Alpha. E.g.,

maximize [{x*q-q^2+a} , {q}]

maximizes the function $$x*q-q^2+a$$ w.r.t. the variable $$q$$.
For further details read the reference sheet of the Maximize function.

You can use Mathematica to solve such problems.