Over a span of 6.0 seconds, a car changes its speed from 89 km/h to 37 km/h. What is its average acceleration in meters per second squared (m/s2)

First, you should convert the initial and final velocities from km/h to m/s. You should end up with Vi = 25m/s and Vf=10m/s (both rounded).

Now, you can use the equation Vf=Vi+A (t)

Rearrange it to A is isolated: A = Vf-Vi/t

A = (10-25) / 6

A=-2.5m/s^2