another quadratic equation

Let f(t) represent the number of new U.S. Hotel openings in the year that is t years since 1990. A possible equation for f is f(t)=-37.36t^2+559.33t-595.31

Find when f(t)=700. What does your result mean in terms of the situation?

Find the t-intercepts of f. What do the t-intercepts mean in terms of the situation.

This is what I have so far...

700= -37.36t^2+559.33t-595.31

Then I subtracted the 700 from the 595.31 which leaves me with this:

-37.36t^2+559.33t+104.69

a=37.36

b=559.33

c=104.69

then I set it up in quadratic formula..but now I am stuck.