@mmcdara I have equilibrium points of 6 differential equations, for  a1-a8 it is an expressions for the other equilibrium points. this eq points i ask about is one of the long equation

@mmcdara can i ask which expression are debatable? if you mean the partial formula, that formula are common use in model epidemiology to find sensitivity of parameters. The expression is to find local sensitivity

@dharr i try run this code on my maple but the result is like this, the simplify not work