how do you find the excluded values of rational expressions, such as 60x^3/12x

Question

mathstudent55 · Answer

Excluded values usually come from denominators and square roots.
In this case, there is a denominator.
A denominator cannot equal zero because division by zero is undefined.
What value of x would cause the denominator to be zero?
To find out, set the denominator equal to zero and solve for x.

anonymous · Answer

if i set the denominator = to 0 then wouldn't the equation become undefined @mathstudent55

mathstudent55 · Answer

No. Don't think of the rational expression.

Think only of the denominator.
Set the denominator equal to zero.
You get:
$12x = 0$

Now solve for x.
Whatever value you get for x is what  you must exclude from the original rational expression because it would result in a zero denominator.

anonymous · Answer

thanks

mathstudent55 · Answer

You're welcome.