1. derivative problem

can someone check my answer
Id check it myself but its a even problem

$
\frac {1}{t^2+3t-1}
$

$
(t^2+3t-1)^{-1}
$

$
-1(t^2+3t-1)^{-2}(2t+3)
$

$
- \frac {2t+3}{(t^2+3t-1)^2}
$

2. Looks correct

3. Try doing the same problem using the 1st principle