How can I rearrange the equation to solve for time?

[einsteinette]

Homework Statement

Rearrange d=vit + 1/2 at^2 for t.

The Attempt at a Solution

t = \frac{-v \pm \sqrt{v^2+4 \left( \frac{1}{2} a\right)d}}{2 \left( \frac{1}{2} a \right)}

 

[Delphi51]

Very hard to read that - but it looks pretty good. I get
t = (-Vi + sqrt(x))/a or (-Vi - sqrt(x))/a
where x = Vi^2 + 2*a*d
I've never seen that formula used - it is just easier to use two of the others to do the job.