How do i Rearranging Equations/formula?

[aquann]

Homework Statement

how would you rearrange this d=v1(t)+ 1/2a(t)^2 for time?

Homework Equations

The Attempt at a Solution

my friend told me it was "-2-v1/a =t" but i don't this is right and if it is right how did he get this?

 

[Delzac]

This is a quadratic equation. Use the quadratic equation formula.