Hm... this is a calculation mistake...

Okay:

0.75 * 9.78 = 7.335

Hence:

7.335 = 9.78 + a

So, a = 7.335 - 9.78 = -2.445 = -2.45 m/s^2

This means that the acceleration has magnitude 2.45 m/s^2 and acting downwards (the answer to the second part),

since I first assumed that the force of the elevator was acting upwards, from here:

Felevator - Weight = ma

Obviously, weight is downwards and I took the up direction as positive.