Symbolic expression not scriptable in Solve

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This is a follow-up to

• Ask Sage question 57318: Use solve with inequality extracted from polytope

The answer by @slelievre to that question works nicely, but I need to use indexed variables.

This variation of the code does not work for me:

D = polytopes.dodecahedron()
DH = D.Hrepresentation()
X = list(SR.var('x_%i' % i) for i in (0..2))
Ineq = [[el.A()*vector(X) >=el.b()] for el in DH]
show(Ineq[0][0])
sol = [solve(Ineq[i][0], x[1]) for i in range(len(Ineq))]

raising an error saying

'sage.symbolic.expression.Expression' object is not subscriptable

Why? the problem doesn't seem to come from Ineq[0][0] but from the variables?