make s subject
t = v√$\displaystyle s^2$+9
this is what im at help me if you can. many thanks
√$\displaystyle t^2$/v-9 = s
Assuming your equation is
$\displaystyle t = v\sqrt{s}^2+9$
then it can be re-written as
$\displaystyle t = vs+9$
as the square ad square root are opposites.
Now taking 9 from both sides
$\displaystyle t-9 = vs$
$\displaystyle vs= t-9 $
and dividing v
$\displaystyle s= \frac{t-9}{v} $
now s is the subject.