Solver App - Newbie needs help

[student0]

Hi guys, I recently got an HP Prime and I am having trouble using Solver App.
My equation is more or less like this: a = (Mz²*Iz-Mz*Iy)/Izy*My
The problem is Mz=800*q, q is unknown variable.
Is it possible solving for "a" in terms of "q" using Solver App? If not, how can I solve it?

PS: I'm really sorry for my bad English

Thank you very much!