How to substitute numerical into symbol?

I need to substitute 0 for certain symbols in an calculation, however it is not doing what I want it to do. The function I have used are listed below as an example:

syms A1 A2 A3 A1_ A2_ A3_

a= A1*A1_+A2*A2_+A3*A3_*2

b= A1*A1_+A2*A2_+A3*A3_

c = subs(a, [A1*A1_,A2*A2_,A3*A3_],[0,0,0])

d = subs(b, [A1*A1_,A2*A2_,A3*A3_],[0,0,0])

but the ans I got is

c =

2*A3*A3_

d =

0

If the symbol on its own, the subs function will work. However, if the symbol is not on its own, such as (A3*A3_)^2 or (A3*A3_)*2, the ans will be similar to c which should be equal to 0 instead of 2*A3*A3_.

Is there anyway or any other function will make the substitution work?