factoring

[jrb47]

I am trying to factor y^2+12y=52
I choose
f2
factor
screen shows:
factor(
I input
y^2+12y+47)
depress enter
and the result is just a repeat of what i put in in this format
y2+12*y+47

This is not the right answer as i am trying to find the x-coordinates on a plot with a distance of x........
I was expecting an answer similar to (a+y)(b+y)

can someone please tell me what i am doing wrong.
Jess