A negative index is the positive index applied to the reciprocal. So, 16^(-3/2) = (1/16)^(3/2)
The denominator of a fractional index represents the relevant root.
Thus, (1/16)^(3/2) = {sqrt(1/16)}3
Now, sqrt(1/16) = sqrt(1)/sqrt(16) = 1/4
So the given number is {1/4}^3 = 1/64.
1 1/2 or 1.5.
1/2
If you mean: y = 3(-3/2)2+9(-3/2)-8 Then: y = -59/4 or as -14.75