Question 1127599
x is increased by a factor of 8.
pick some numbers
x=k/z^3, let x=8 when z=4
8=k/64; k=512
Let z now be 2
x=512/8=64.  That is 8 times the original x
it is 1/z^3, and when z is half of that it is 1/(1/8) or 8.

When z is decreased by (1/2), x is increased by 1/(1/2)^3 or 8 fold.