Question 890532
The rational expression is undefined when the denominator is zero. So set that equal to zero and solve for x


{{{x^2-6x+8=0}}}


{{{(x-4)(x-2)=0}}}


{{{x-4=0}}} or {{{x-2=0}}}


{{{x=4}}} or {{{x=2}}}


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The rational expression is undefined when either {{{x=4}}} or {{{x=2}}} since these values cause the denominator to be zero (and you cannot divide by zero)