Answer:
x = 3
Step-by-step explanation:
What you wrote, x + 8/x - 3 means [tex] x + \dfrac{8}{x} - 3 [/tex].
I assume you didn't mean that, but instead, you mean
[tex] \dfrac{x + 8}{x - 3} [/tex], so I'll use this expression in the problem.
A fraction cannot have zero in the denominator since division by zero is undefined and not allowed. The denominator of the fraction is x - 3.
We need to find which value of x makes the expression x - 3 have a value of zero. Then that is the value of x that must be excluded from the domain.
We set the denominator equal to zero, and we solve for x.
x - 3 = 0
Add 3 to both sides.
x = 3
A value of 3 used for x makes the denominator equal zero, so the real number for which the expression is undefined is
x = 3.
