# What is the value of maximum possible value of x minus minimum possible value of x

If x is an integer and 9<x^2<99, then what is the value of maximum possible value of x minus minimum possible value of x?
A. 5
B. 6
C. 7
D. 18
E. 20

Also tricky. Notice that $x$ can take positive, as well as negative values to satisfy $9, hence $x$ can be: -9, -8, -7, -6, -4, 4, 5, 6, 7, 8, or 9. We asked to find the value of $x_{max}-x_{min}$, ans since $x_{max}=9$ and $x_{min}=-9$ then $x_{max}-x_{min}=9-(-9)=18$.