I understand that in asin(bx + c) + d, where c represents the phase shift. But then in a question like:

f(x) = 7sin[6(x + pi/12)] + 3

the phase shift here is pi/12 (I thought it was pi/2)

and

f(x) = -3sin(2x + pi/2) - 5

the phase shift here is pi/4...again I thought it was pi/2. So how exactly do you find the phase shift...?

NOTE: I know how to sketch the graph of such, the question, though, is not asking me to sketch the graph, it is simply asking for the phase shift.

Thanks in advance