S+ut+1/2 at?(m) u=5, a=12, t(sec)=3 find value of s=?

Dear student,
Substituting the given values in above equation:
$$\begin{gathered} S=ut+\frac{1}{2}a{t}^2 \\ S=\left(5\right)\left(3\right)+\frac{1}{2}\left(12\right)(3{)}^2 \\ S=15+\frac{1}{2}(108) \\ S=15+54 \\ S=69m \\ Regards \end{gathered}$$