restrictions are not allowed values
the most common restrictions are sqrt of a negative and dividng by zero
since there are no sqrts in this quesiton, see whicch value of x will make us divide by zero
x-4/x+1
denom=0 to find restricted value
x+1=0
minus 1
x=-1
the restricted value is x=-1
basically
x=all real numbers except for -1
