KeYmaera X uses backend tools to prove validity of real arithmetic formulas. Z3 is shipped with KeYmaera X for your convenience. Please select your preferred solver.
Limited functionality with Z3.
For advanced functionality, such as counterexample generation, monitor synthesis, test case generation, simplification, and arithmetic with alternating quantifiers please choose Mathematica or Wolfram Engine as Arithmetic Solver from the options above.
In general, complex problems may require trying different tools.