A RATIONAL EXPRESSION is an expression without a fraction or a square root
in the numerator or denominator. It is often expressed as a fraction of polynomials.
For example:
Feel free to turn down the music if you get annoyed by it.
This is very important!
Back in the video, recall when we factored the denominator to:
(x + 6) (x - 1)
So this means that if we had x = 1 or x = -6, that set of parentheses
would equal 0, and make the entire denominator = 0
BUT
We can't have the denominator = 0, because then we would have an
undefined expression.
This means that 1 and -6 are EXCLUDED VALUES; x-values that
would make the expression undefined. It's what makes the bottom of the
fraction 0, not the top. If the top is zero, then the expression IS ZERO,
and not UNDEFINED.
The real answer to the video is:
Remember to check for excluded values whenever you simplify
rational expressions!
Scroll down for the answer
they are -5 and -6
