[tex]s = ut + \frac{1}{2} a {t}^{2} \\ \\ \frac{1}{2} a {t}^{2} = s - ut \\ \\ a = (s - ut) \: \div (\frac{1}{2} {t}^{2}) \\ \\ a = (s - ut) \: \times ( \frac{2}{ {t}^{2} } ) \\ \\ a = \frac{2s - 2ut}{{t}^{2}} \\ \\ a = \frac{2s}{{t}^{2}} - \frac{2ut}{{t}^{2}} \\ \\ \\ a = \frac{2s}{{t}^{2}} - \frac{2u}{t} [/tex]
I hope I helped you^_^
