If x^2=x -1, then x^3=? Choose the correct choice:
A) 3x+2
B) 3x-2
C) 2x+1
D) -1
E) 3x+4
Given X^2 = X - 1   X^3 = X*X^2 = x*(X-1)-- Substituted from above.   = X^2 - X = X-1-X = -1.   Hence -1.
<result>D</result>
If x^2=x -1, then x^3=?