Please solve fast. I will mark brainliest

Simplify. (-2)^-3 a. -8 b. -1/8 c. 1/8 d. 8

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?

An observer(o) spots a plane(p) taking off from a local airport and flying at a 29 degree angle horizontal to her line of sight and located directly above a tower(t). the observer also notices a bird circling directly above her. if the distance from the plane(p) to the tower(t) is 6,000ft., how far is the bird(b) from the plane(p).