Calculators with equation storage and multi-letter variable names

[celltx]

Casio 9750GIII and CG50 both have a nice solver that solves for any variable. However variables names have only one letter.

On the positive side, Casio has a powerful e-Activity applications that basically integrates all other applications, including the solver, with a notepad-like text interface. So, even though you can't have long variable names, you can put a descriptive text that explains their meaning in a specific context A single e-Activity doc can have as many solver stripes inside as you want and not limited by 20 equations like in HP Prime. One can have many e-Activity docs too. Very useful integration feature.