Answer
$s=-\displaystyle \frac{3}{2}$ or $s=2$
Work Step by Step
We solve by factoring:
$2(s+1)^{2}-5(s+1)=3$
$2(s+1)^{2}-5(s+1)-3=0$
$[2(s+1)+1][(s+1)-3]=0$
$(2s+2+1)(s+1-3)=0$
$(2s+3)(s-2)=0$
$2s+3=0$ or $s-2=0$
$s=-\displaystyle \frac{3}{2}$ or $s=2$