How can we write the following cost function in cvx?

Nonconvex
1

Minimize (a+x)^u
a constant
x, u variables

2

I forgot to write
1<= u<= 2
X>0
Also, i simplified my cost function, if it is necessary I can write it again
Thanks

3

x^u where x and u are both optimization variables is neither convex not concave; so can;'t be used in CVX.

4

Thanks for your kind reply.
Is it possible to use ADMM Algorithm? It can use for both convex and nonconvex

5

That really doesn’t have anything to do with CVX, so is best discussed elsewhere.