Verified answer

✐Derivation✐

Subtract both sides by Vi t

d - Vi t = ½at²

Multiply both sides by 2/a.

(2d - 2Vi t)/a = t²

Set the equation to the power of 1/2. Simplify.

±√(2d - 2Vi t)/a = t

Try solving for a by yourself.

Subtract d from both sides and now you have a quadratic equation for t. Using the quadratic formula. Solving for a - subtract vi t from both sides and do a little algebra.