(2/3)^1998*(-1.5)^1999÷(-1)^2000
=(2/3)^1998*(-3/2)^1999÷1
=(2/3)^1998*(-3/2)^1999
=(2/3)^1998*(-3/2)^1998*(-3/2)
=(-3/2*2/3)^1998*(-3/2)
=(-1)^1998*(-3/2)
=1*(-3/2)
=-3/2
(2/3)^1998*(-1.5)^1999÷(-1)^2000
=(2/3)^1998*(-3/2)^1999÷1
=(2/3)^1998*(-3/2)^1999
=(2/3)^1998*(-3/2)^1998*(-3/2)
=(-3/2*2/3)^1998*(-3/2)
=(-1)^1998*(-3/2)
=1*(-3/2)
=-3/2