[tex]\dfrac{5}{2s} + \dfrac 3 4 = \dfrac{9}{2s}[/tex]
Common denominator 4s, let's multiply through,
[tex]10 + 3s = 9[/tex]
[tex]3s = -1[/tex]
[tex]s = -1/3[/tex]
Check:
5/(-2/3) + 3/4 = -15/2+3/4 = -27/4
9/4s = 9/(-4/3) = -27/4, good
Answer: s=-1/3
