原式=-0.125^8 x 2^24 x2 =-0.125^8 x 2^(3x8) x2 =-0.125^8 x(2^3)^8 x2 =-0.125^8 x8^8 x2 =-(0.125x8)^8 x2 =-1^8 x2 =-1x2 =-2
