y = (3x + 1)^2
and
y = (2x - 5) / (3x + 2)^2
OK. Good. You've found the derivative $\displaystyle y'=18x+6$. (Don't forget the apostophe, marie. It let's peolpe know that this is the derivative.)
Now, all ya gotta do to find the slope is to plug in 1. IE $\displaystyle y'=18(1)+6$. This gives you the slope.
As far as, $\displaystyle y=mx+b$ is concerned, we don't need it here because all we want is $\displaystyle m$. The rest of the equation doesn't concern us. Got it?