For what values of x is the rational expression below
undefined?

Answer: The rational expression below is undefined when x is equal +5 and -5.
Step-by-step explanation: The rational expression will be undefined when the denominator is equal to zero. So, first you have to take the denominator and make it equal to zero.
[tex]3x^{2} -75=0\\[/tex]
Then you divide the whole thing by three to get this:
[tex]x^{2} -25=0[/tex]
Now you move 25 over to the other side of the equation and take the square-root of both sides.
[tex]x^{2} =25\\x= +/- \sqrt{25}[/tex]
Since the square root of 25 is equal to five. We know that the rational expression will be undefined when x= -5 and +5