Question 107517
Please help me find all numbers for which the rational expression is not defined. x^2-3x-4 over x^2-18x+77. 
:
{{{(x^2-3x-4)/(x^2-18x+77)}}}
:
The expression is undefined when the denominator = 0
Find the values of x which make the expression {{{x^2 - 18x + 77}}} = 0
:
{{{x^2 - 18x + 77}}} = 0
Factors to 
(x - 11)(x - 7) = 0 
x = +11
and
x = +7
:
Substituting these two values for x; makes the denominator = 0; hence undefined