Show that the expression vf = vi + at is dimensionally correct

To show that the expression given is dimensionally correct, we can do a dimensional analysis where we write the units of each term in the expression.

vf [=] vi + at 
m/s [=] m/s+ (m/s²) (s)
m/s [=] m/s+ m/s
m/s [=] m/s

Therefore, the expression is dimensionally correct.

By dividing you can find the answer