Hello,  after almost a decade not using Maple, I am trying to get going to solve a set of differential equations and I have some problems that are probably pretty basic.

1.  I have the following simplification equations

which rightfully gives

and

which I hoped would give

but gives

"Error, invalid left hand side in assignment".  What am I doing wrong?

2.  The above simplification equations will be used to simplify this vector:

Once I get passed the "Invalid left hand side assignm,ent" issue, I would like to reorganize each line of the above vector and simplify using the small equations above.  What command do I need to use to do this?  The Phi & Beta variables are not necessarily next to one another so the equations need to be reorganized and the substitution for Omega & Omega_dot done.

Any help is appreciated! Thanks