Problem with using subs() for products of symbolic variables

I have a question regarding the use of the subs function in the symbolic toolbox. It seems to have trouble with products of symbolic variables. For example, I would expect

>> subs(3*a*b+b,a*b,0) to produce b

Instead, it produces: b + 3*a*b

Can this be remedied?

Answer 1

[Andrei Bobrov]

use function subsex by MuPAD

out = feval(symengine,'subsex', b + 3*a*b, 'a*b = 0')

[James]

Thanks! That works just fine.

Answer 2

[Felipe G. Nievinski]

see http://www.mathworks.com/support/solutions/en/data/1-EE934O/index.html?product=SM&solution=1-EE934O