Using 'if' statement with two conditions

Hi,

I want to use and if statement in COMSOL but I need it to have two conditions.

I want to calculate the value of the x coordinate when y = 0 and T=300.
Something like:
if(y ==0 and T == 300, xi == x)

Would the AND logical operator (&&) work instead of the and in my above statement?
No matter what I try I get errors.

Someone mentioned in a previous post that my if statement must not contain discontinuities and that they can be avoided by combining the if and sens operators, I don't understand how to do this though.

I would really appreciate some help with this problem!

Thanks,
-Adam.