What is the largest value of $x$ such that the expression \[\dfrac{x+1}{8x^2-65x+8}\] is not defined?

The expression is undefined when its denominator is zero. The denominator factors as
  (x-8)(8x -1)
so it will be zero for x = 1/8 and x = 8.

The largest value of x for which the expression is undefined is 8.

The question is kind of confusing. if it's asking how many variations of answers can you give. then do 4^5 for your answer.this would be something like the first question could be a and the 2nd c or first b next c etc. if you can, ask the teacher for a better confirmation of what it's asking. if i'm assuming correctly what it's asking, it's 625 different variations.