With the usual notations, the following equation St=u+12a(2t−1) is

We can derive this equation from equations of motion. So it is numerically correct.St= Distance travelled in tth  second = Distance  Time =Lu= Velocity =LT−1 and 12a(2t−1)=LT−1As dimensions of all terms in the given equation are not same, hence equation is not dimensionally correct.