Example  2

Determine the non-permissible values for the expression \(\frac{5}{3x^2 - 6x}\).


Step 1: Factor the denominator.

In this example, in order to determine the NPVs, you must factor the denominator.

\[\frac{5}{{3x^2 - 6x}} = \frac{5}{{3x\left( {x - 2} \right)}}\]

Step 2: Determine the values of \(x\) that cause the denominator to equal zero.

\(\begin{align}
 3x &\ne 0 \\
 x &\ne 0 \\
 \end{align}\)

\(\begin{align}
 x - 2 &\ne 0 \\
 x &\ne 2 \\
 \end{align}\)

The NPVs are \(0\) and \(2\). This expression is written as \(\frac{5}{{3x^2 - 6x}}, \thinspace x \ne 0, \thinspace 2\).