How do you determine the values for which a rational expression is undefined? This is relating to simplify rational expressions.

Question

anonymous · Answer

Anything that would make the denominator zero.

anonymous · Answer

alright this one always gets me too! lets say your fraction is 8/0, your answer would be undefined. however, if it was 0/8 your answer would be 0

anonymous · Answer

Why wouldnt it be 0 in both cases? and how would that relate to equation type problems such as 8x+5/4x+10 (just an example, not an actual problem.)

anonymous · Answer

It would not be zero in both cases. This is because 8/0 is asking how many times zero can go into 8 and zero cannot go into anything ever, so it is undefined. 0/8 is asking how many times eight can go into zero, because eight can go into other numbers, but in this case cannot go into zero, the answer is zero. This is the best I can explain the rule. In the case of (8x+5)/(4x+10) you would set your denominator equal to zero. So, $$4x+10=0$$ then $$4x=-10$$finally you divide by four and simplify to get $$x=-\frac{ 5 }{ 2 }$$

anonymous · Answer

$$x=-\frac{ 5 }{ 2 }$$ means that is where the equation would be undefined

anonymous · Answer

8 cant do into 0, but 0 can go into 8, which is why its like that. and in an equation like that you would have a variable so it would be a little different

anonymous · Answer

cant*