Anything to a negative power becomes the inverse with the coefficient to a positive power.
For example, 3^-1 becomes 1/3^1 or just 1/3.
3^-2 would be 1/3^2 or 1/9.
The answer is -8 (-8=2*-4)
2.43 x 10^2
Hope this helps
Pm me i ne more info,,, is there some missing ?