Manipulation of technical formulee

Rules for manipulating formulas 

1. What you do on the one side of the equal sign you must do on the other side.
2. If you must make an exponent the subject, you use logs.
3. The inverse operation of a 'root' is a 'power'.
   $\text{T}heinverseof\sqrt[3]{}is({)}^3$

Make u the subject of:

$v=u+atv-<!--\; -\; -->at=u\therefore <!--\; \therefore \; -->u=v-<!--\; -\; -->at$