Hi, all,
I have a question about how to evaluate result of expression containing ROOTOF.

for example:
>alias(x = RootOf(Z^3+Z+1))

>A := a[2]*x^2+a[1]*x+1

>B := b[2]*x^2+b[1]*x+1

>M1 := A*B;

>expand(M1);
a[2]*x^4*b[2]+a[2]*x^3*b[1]+a[2]*x^2+a[1]*x^3*b[2]+a[1]*x^2*b[1]+a[1]*x+b[2]*x^2+b[1]*x+1
>evala(expand(M1));
x^2*(1+b[2]-b[1]+a[2]*b[1]*x+a[2]*b[2]*x^2+a[1]*b[2]*x+a[1]*b[1]+a[2]-a[1]-a[1]*x^2-x^2*b[1]-x+x^2)

I have questions about expand(M1) and evala(expand(M1)).
>expand(M1);
a[2]*x^4*b[2]+a[2]*x^3*b[1]+a[2]*x^2+a[1]*x^3*b[2]+a[1]*x^2*b[1]+a[1]*x+b[2]*x^2+b[1]*x+1

How can we make the result look better, I mean in a better order, like:
(...)*x^2+(...)*x^1

>evala(expand(M1));
x^2*(1+b[2]-b[1]+a[2]*b[1]*x+a[2]*b[2]*x^2+a[1]*b[2]*x+a[1]*b[1]+a[2]-a[1]-a[1]*x^2-x^2*b[1]-x+x^2)

Why are there brackets in the result which is actually a fully expanded expression.

Thanks a lot.