Inductance: Current in terms of Voltage

[a3sportback54]

I'm having a bit of trouble getting the right answer for a problem in my electrical engineering textbook. The question is:

At t=0, the current flowing in a 0.6H inductance is 8A. What constant voltage must be applied to reduce the current to 0A at t=0.4s.

I'm using the equation:

i(t)=\frac{1}{L}\int\ v(t).dt+i(t_{0}) with limits 0.4s and 0s

The answer I'm getting is 12V, and the book says 10V.. which is right??

I'm using L=0.6H, i(t0)=8A, and i(t)=0A

Please help!

 

[CEL]

It seems the book answer is wrong. And so is yours. The correct answer would be -12V.