Now this is a simplification:

[DrD]

[CAS]
diff((3*x^2-4)^100,x); ==> 100*3*2*x*(3*x^2-4)^99

This was fun:

Code:

simplify([b]diff((3*x^2-4)^100,x[/b])); //  ... quick, SHUT THE DAMN DOOR !!!!
PRINT(Ans);

This seems MUCH simpler than simplify():
collect(diff((3*x^2-4)^100,x)); ==> 600*x*(3*x^2-4)^99

Now try this (automatically simplified (collected) result):
y:=diff((3*x^2-4)^100,x); ==> 600*x*(3*x^2-4)^99

Without assignment the expression produces a non-collected result. By simply assigning the expression to a variable, a collected result is saved.

-FYI-