I converted 12ms to

**0.012s**. Then I listed what is known in the problem. The initial velocity is

**3m/s**and the final velocity is

**-2m/s.**

I know the equation for acceleration is

**Vf-Vi/Tf-Ti.**

But the answer that I get is

**-417m/s^2.**

The question is multiple choice and none of the answers match this.

What am I doing wrong here?