Can someone please help me with this problem. I tried all day and couldnt get the correct answer. Thanks for your help!

Question: While chasing Mitch for destroying his bike, Skid does the following to his Pinto: He starts from rest and accelerates at 0.6 m/s^2 for 15 sec. Travels at a constant velocity for 2 mins. Slows to a stop with an acceleration of -.75 m/s^2. What is the total distance Skid travels?

What I did so far: v = v not + at

= 0 + (.6)(15)

= 9 m/s

x = x not + v not t + 1/2 at^2

= 9 (120s) = 1080 m

v = v not = at

-9 = -.75t

t = 12 sec

Then I plug 12 sec to the formula x = x not + v not t + 1/2 at^2 and got a weird number. I am really stuck. Thanks again for your help!