You can
put this solution on YOUR website! Find the real number for which each rational expression is
undefined.
5x+9
-----------
4x²-4x-15
A rational expression is undefined if its denominator is 0.
So set the denominator = 0 and solve for x.
denominator = 4x² - 4x - 15 = 0
The left side factors as
(2x + 3)(2x - 5) = 0
Use to zero-factor principle. Set each factor = 0 and solve:
Setting 2x + 3 = 0 gives x = -3/2
Setting 2x - 5 = 0 gives x = 5/2
Therefore the expression is undefined for x = -3/2 or 5/2
Edwin
AnlytcPhil@aol.com
