### Home > CCA2 > Chapter 3 > Lesson 3.2.4 > Problem3-102

3-102.

1. Explain to Estacia why $x$ cannot be $4$ in the expression $\frac { x + 2 } { x - 4 }$.

What happens when you substitute $4$ for $x$?

$4$ does not work here because it makes the expression undefined since dividing by $0$ is not possible.

2. Find the excluded values of $x$ in each of the expressions of problem.

What values make the denominator equal to $0$? These are known as excluded values.

3. Create an expression that has the excluded values of $x\ne−6$ and $x\ne\frac{1}{3}$. Be prepared to share your expression to the class.

Answers vary. Make sure that these two values make the denominator equal to $0$.