another problem.... please explain...?

Question

What is the domain of (3x-1) / [x (5+x)] ?

Answer 1

this can be defined for all values of x, except where the denominator of the fraction is equal to zero, in which case,

x(5+x) = 0, so the inital function is undefined where x=0 and x=-5.
You may restrict the domain to real values of x if you like also.

Answer 2

All real numbers except x=0 and x= -5 beause at those point the denominator is zero and you can´t divide by zero