This week in PreCalc 11, we learned about finding the Non-Permissable Value in a Rational Expression/Equation. To do this when given the equation you have to, first of all, simplify/factor the farthest you can before trying to find the Non-Permissable Value. This way you can see if you can cross out any matching pairs.

However, you still need to find the Non-Permissable Value for that pair, because there is a Non-Permissable Value for every denominator (NPV’s only apply to the denominator). Therefore in the example the NPV is x ≠ -10 because both of the fully factored equation on the denominator is (x + 10) and you are just solving for x so -10.

However, my mistake for this week is that when I was solving for the Non-Permissable Value/X I did not switch the sign when switching it to the other side to solve for the x.

For example: