Sole Cads or Not To CAS

[C.Ret]

(06-09-2022 10:47 AM)tim_crouse Wrote:  According to the tutorial, I'm on Udemy, the answer is -1.

This is the correct answer to the problem.
I get this solution in HOME as well as CAS mode.

In HOME mode, numerical solutions are preferred based on standard 12-digit machine arithmetic.

In CAS mode, by default, the HP Prime first tries to solve the equation symbolically.
In the simple examples, this approach leads to the same simple numerical solution(s). The only advantage of CAS in these cases is the ability to answer exact or exact long integers.
In CAS, the numerical answer can be forced, it is enough to indicate a guessed value for the variable to be solved.

But the real advantage of CAS mode is to used it for step by step symbolic resolutions (see capture).



In jonmoore's screenshot, we can see that he answers another problem where the unknown x is only present in the left side of the equation. That's why he gets a different solution.

Here are screenshots of the original tim_crouse problem in the SOLVE application, real resolution in CAS mode step by step or using the SOLVE command:    

P.S.: I type 2x and (-)4X directly without any implicit multiplication sign. But the Hp Prime feedback systematically add any multiplication to indicate, without any ambiguity, its interpretation of my inputs.