I am trying to integrate this with respect to time - t

Note: t is equal to 600-t

$\displaystyle v(t) = -35-100 \frac {dv}{dt} $

I tried to integrate it and got this

$\displaystyle d(t) = -35(600-t)-100v(t) $

somehow i it should be

$\displaystyle d(t) = 100v(t)-35(600-t) $